WO1997005675A1

WO1997005675A1 - Electrical connection between printed circuit boards

Info

Publication number: WO1997005675A1
Application number: PCT/GB1996/001781
Authority: WO
Inventors: Gary Frank Sinfield
Original assignee: Cinch Connectors Ltd
Current assignee: Cinch Connectors Ltd
Priority date: 1995-07-25
Filing date: 1996-07-25
Publication date: 1997-02-13
Anticipated expiration: 1998-01-25
Also published as: GB9615638D0; GB9515234D0; GB2303748A; AU6620196A

Abstract

Circuit boards are connected perpendicularly by means of a planar connector member (12) comprising a board with through holes containing wads of wire.

Description

Electrical Connection Between Printed Circuit Boards

The present invention relates to the interconnection of printed circuit boards and more particularly to such an interconnection utilising conductive parts incorporating resilient wads of wire for electrically interconnecting the boards. Mechanical interconnection is achieved separately from electrical interconnections.

Conventionally when interconnecting two printed circuit boards together for example when interconnecting a daughter board to a mother board, a socket type device is attached to the mother board which has resilient contacts. The daughter board is then inserted into the socket overcoming the spring force of the resilient contacts as it is inserted. This type of interconnection is convenient as it provides both electrical and mechanical connection between the two boards but it can result in extremely high insertion forces being required.

The present invention has, as an object, the provision an interconnection system which will substantially reduce insertion forces.

In order that the present invention be more readily understood, an embodiment thereof will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a general arrangement of a daughter board connected to a mother board according to the present invention;

Figure 2 shows a part of a daughter board according to the present invention;

Figure 3 shows a diagrammatic exploded plan view of the connector arrangement shown in figure 1.

The present invention will be described in relation to the interconnection of a daughter board to a mother board but this terminology is not to imply any restriction on the relative sizes or uses of the two boards. The present invention is applicable to any number of different sizes and types of board.

As shown in figures 1 and 3, a mother board 10 is connected to a daughter board 11 by means of an interconnection system generally indicated by the reference numeral 12. The interconnection system comprises interconnector board 14 provided with a number of through holes 15 which contain wads of wire 16 which project from either side of the board 14 when uncompressed. The interconnection system 12 is attached to the mother board 10 by any convenient arrangement such as one or more clamping screws 18 which extend through holes 19 in the mother board to engage with threaded holes 20 in the board 14. If desired, guide pins can be provided in order to locate the interconnection broad 14 on the mother board prior to clamping and, as shown in figure 3, the interconnection board 14 can be provided with one or more guide pins 22 which are received in holes 23 in the mother board.

With the arrangement as described thus far, the wads of wire 16 make contact with conductive tracks on the surface of the mother. It is to be emphasises^ that these conductive tracks are conventionally on the major surface or surfaces of the printed circuit board.

If we now turn to the daughter board, the construction of the daughter board is somewhat unusual and if one looks at figure 2 it will be seen that the conductive tracks on the major surface or surfaces of the daughter board are extended onto the edge surface as indicated by the conductors 26. The extent by which the conductive tracks 26 extend onto the edge surface is only significant when the conductive tracks 26 have to be closely spaced together in which case it is convenient if alternate tracks are longer so as to permit the conductive wads 16 to be patterned in such a way as to make contact with conductive tracks 26 which are closer spaced together than would be possible due to the diameter of the holes 15 in the interconnection board 14.

In addition to normal conductive tracks 26 it is also possible to provide interconnections equivalent to coaxial connections as indicated by the conductive patterns 28 where the outer, U-shaped pattern represents the ground conductor.

As in the case of the mother' board, a mechanical guide arrangement between the daughter board and the interconnection board 14 can be provided. As shown in figure 3 this consists of further guide pins 28 on the interconnection board 14 which are received in recesses 29 in the daughter board.

Although not shown in the drawings, some form of mechanical clamping is required in order to hold the daughter board against the interconnection board 14 against the force of the resilient wads of wire which come into contact with the conductive tracks 26 and 28.

It will be appreciated that because the only insertion force required is the small force to compress the resilient wads of wire, an extremely high number of interconnections can be made while still maintaining very low insertion forces. Further, this is a solderless interconnection but with very good electrical properties. Due to its compact nature, the interconnection system 12 can be very compact and hence small boards can be interconnected very conveniently.

Claims

CLAIMS:

1. An assembly of two or more printed circuit boards in which at least two of the boards are connected to each other by means of a generally planar connector member having electrically conductive means extending from one of its major surfaces to the other.

2. An assembly as claimed in Claim 1 in which the connector member has a number of through holes containing said electrically conductive means.

3. An assembly as claimed in Claim 2 in which said electrically conductive means comprise wads of wire.

4. An assembly as claimed in Claim 1, 2 or 3 in which said at least two boards are positioned peφendicular to each other, with the connector member lying parallel to one ofthe boards.

5. An assembly as claimed in Claim 4 in which one ofthe boards has conductive tracks extending onto one or more of its edge surfaces, at least some of which contract said electrically conductive means.

6. An assembly as claimed in any preceding claim in which one ofthe boards is mechanically clamped to the connector member.

7. An assembly as claimed in any preceding claim including guide means for locating the or each of said at least two boards with respect of the connector member.

8. An assembly as claimed in Claim 7 in which the guide means comprise cooperating pins and holes.

9. An assembly as claimed in Claim 5, or any of Claims 6 to 8 when dependant on claim 5 wherein altemate conductive tracks on said one of the boards are longer than the other tracks.

10. An assembly as claimed in Claim 9 wherein said electrically conductive means are arranged to contact the ends of the tracks.

11. An assembly as claimed in Claim 5, 9 or 10 or any of Claims 6 to

8 when dependant on Claim 5 wherein said tracks include U-shaped tracks encircling the ends of other tracks.

12. An assembly substantially as herein before described with reference to the accompanying drawings.