Connection system for printed circuit boards

The present invention relates to a system for providing input-output paths to and from a densely crowded multi-lager PCB (printed circuit board). More particularly the invention includes a pair of modules having a plurality of spaced conductive members extending normally therethrough and with the ends projecting laterally from opposing sides. The ends of the conductive members are inserted into plated through holes in the PCB on one side and into plated through holes on cards on the other sides. The cards have circuits extending from the plated through holes to an edge as does the PCB. The two cards and PCB are plugged into card-edge connectors as a unit. The connectors may be mounted on a mother board, back panel or the like.

BACKGROUND OF THE INVENTION 
1. The Field of the Invention 
The present invention relates to the art of increasing the number of 
input-output signal for a PCB. 
2. The Prior Art 
There is no known prior art directed to the invention disclosed herein. 
SUMMARY OF THE PRESENT INVENTION 
The present invention discloses a system for dramatically increasing the 
number of available input-output signal paths for a printed circuit board. 
A pair of modules having a plurality of conductive members extending 
through an insulative housing cooperate with a pair of cards so that each 
printed circuit board has in effect three edges adapted for being 
connected to card-edge connectors.

DESCRIPTION OF THE PRESENT INVENTION 
The card cage 10 shown in FIG. 1 contains six connection systems 12 of the 
present invention. The systems connect the circuitry on each of the three 
PCB 14 to other circuitry (not shown) via pins 16 projecting through the 
top and bottom surfaces 18 of the cage. The other circuitry may be on a 
mother board into which pins 16 will be inserted or the pins 16 may be of 
the type suitable for wire wrapping. 
The back of the cage is broken away to illustrate one method by which power 
is provided. One or more buss bars 20 are plugged into power modules 22 
positioned on and connected to each PCB 14. The bars extend across the 
back of the cage and may be fastened to the walls thereof if required. 
FIG. 2 shows one connection system 12. The system comprises a pair of 
modules 24, and two cards 26. Card edge connectors 28 and cage 10 
complement the system but are not part of the invention. 
FIG. 3 discloses the system in greater detail. The modules 24 include 
elongated housings 30 of insulating material such as VALOX, a glass-filled 
plastic sold by General Electric under that tradename. Two rows of 
elongated, conductive members 32 are embedded normally in the housing with 
the ends 34 projecting out from both sides. These members are preferably 
made from phosphor bronze. A narrow shield 36 is embedded in the housing 
between the two rows or rods. The shield, preferably made from copper, 
runs for the full length of the housing and is positioned inwardly from 
both sides. Pins 38, formed integrally with the shield at spaced 
intervals, extend from the shield to outside the housing along one side 
indicated by reference numeral 40. The housing also has a slot 42 on 
opposite side 44. The slot is located between the two rows of conductive 
member ends on that side. 
Cards 26 are elongated printed circuit board cards of short height. Three 
rows of plated through holes 46 are provided along with conductive 
circuits 48 which extend from the holes to lower edge 50 of the card. As 
is well known in the art, PCB 14 also contains plated through holes 46 and 
conductive circuits 48. 
The connection system of the present invention may be assembled by plugging 
the two modules into opposite sides of PCB 14. As shown in FIG. 3 one 
module is displaced vertically with respect to the other, the displacement 
being such that one row of ends 34, which extend through the board, are 
received in slot 42 in the module on the opposite side of the board. 
Obviously one module could be displaced far enough vertically to avoid the 
slot requirement; however as noted above, PCB 14 is densely packed and 
every bit of board space must be fully utilized. 
Where ends 34 include a compliant section such as disclosed in U.S. Pat. 
No. 4,186,982, the insertion into plated through holes 46 provides both 
the required electrical connection and mechanical retention. 
Cards 26 are plugged onto sides 40 on the two modules, with ends 34 and 
pins 38 entering the appropriate plated through holes in the cards. 
Obviously the cards can be attached to the modules before attaching the 
modules to the PCB. 
The assembly as shown in FIG. 3 is duplicated on the other edge of PCB 14 
to provide the system shown in FIG. 1. 
Card edge connectors 28 shown in FIGS. 1 and 2 are ideally suitable for use 
with the system disclosed herein in that the card edges are slid in rather 
than top-loaded as required by other type card edge connectors. Connectors 
28 are sold by AMP Incorporated of Harrisburg, Pennsylvania under the name 
of Zero Insertion Force Edge Connector-Lever Style. 
The system disclosed herein provides a means for greatly increasing the 
number of input-output signal paths for a densely packed printed circuit 
board without increasing the board's size nor decreasing the board's 
circuitry. The system can also be used on just one edge of a printed 
circuit board. Further the system may be used on a printed circuit board 
that does not have an edge adapted for insertion into a card-edge 
connector. Further just one module and one card may be used on one side of 
a PCB if required. 
It is to be understood that the forms of the invention shown and described 
herein are but preferred embodiments thereof and that various changes and 
modifications can be made therein without departing from the spirit or 
scope of the invention.