Electrical connectors – Metallic connector or contact having part permanently... – Adapted to be secured to conductor formed on printed circuit...
Patent
1992-09-21
1994-09-06
Desmond, Eugene F.
Electrical connectors
Metallic connector or contact having part permanently...
Adapted to be secured to conductor formed on printed circuit...
29846, 439 83, H01R 402, H01R 909
Patent
active
053443438
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to solder-bearing contacts and leads for attachment to contact pads on substrates such as electronic circuit boards, chip carriers, or the like.
2. Description of the Related Art
In the electronic equipment industry, it is known to provide leads for connection to contact pads of printed circuit boards and other substrates by soldering the leads thereto. See, e.g. U.S. Pat. Nos. 4,728,305 and 4,597,628. However, as the electronic industry continues to move toward greater miniaturization, the size and spacing between the contact pads has accordingly been reduced. This requires a correspending reduction in the size and spacing of the leads which are tc be connected to contact pads.
However, in attempting to reduce the spacing between leads, it is also important to provide sufficient spacing to prevent inadvertent contact or arcing between adjacent leads.
The objective of size/space reduction of the leads must be achieved without sacrificing accuracy in manufacture of the leads. It is also desirable to provide rapid assembly of multiple leads. Prior construction and manufacturing processes of leads have been unable to achieve effectively the required reduced size and spacing.
Thus, the need exists for effectively applicable leads of reduced size and spacing to accommodate the current reduction in the size and spacing of contact pads of substrates, but sufficiently spaced to prevent arcing. The need also exists for a method of manufacturing such leads without sacrificing accuracy.
SUMMARY OF THE INVENTION
The present invention overcomes the problems and deficiencies of the prior art by providing solder-bearing leads of reduced size and spacing to acconunodate current reductions in the size and spacing of contact pads of printed circuit boards, circuit chips, or other substrates. The leads may be formed from a continous metal strip by progressive stamping. The solder-bearing portion of the lead of the present invention in one form includes a pair of projections extending from one edge to form a gap therebetween which is dimensioned to receive and retain a solder mass. A region of a portion of the lead is twisted so that the edge of the solder-bearing portion containing the projections is bent so that the projections lie in a plane substantially perpendicular to the plane of the remaining portion. Since the thickness of the lead when initially formed is less than its width, the twisting of the solder-bearing portion results in a lesser width of that portion adapted to contact the substrate and permits closer spacing of leads. A solder mass is placed and held within the gap between projections of the solder-bearing portion to provide electrical bonding between the lead and the substrate.
In a modified form, the projections referred to may be dispensed with or modified to eliminate any gap. Instead, the solder is applied as one or more stripes on the continuous strip from which the leads are formed, before stamping and twisting. The solder-bearing portion of the lead after twisting is adapted to be applied to the contact pad with the edge of the lead and its adjoining solder stripe or stripes applied against the contact pad.
The solder-bearing lead can be used inter alia as an edge clip for securing to a substrate or for surface mounting on the substrate. The solder-bearing lead can advantageously be made by automatic progressive stamping of blanks at high speed and simple twisting of the lead. The leads may be readily configured to be attached to a carrier strip and for group attachment to a substrate, with provision thereafter to remove the solder-bearing and terminal portions of the lead from the carrier.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects, features, and advantages of the present invention will be more completely disclosed with reference to the following detailed description of presently preferred embodiments of the present invention, taken with the attached drawings, in which:
FIG. 1A shows a plan view of a continuous
REFERENCES:
patent: 3915546 (1975-10-01), Cobaugh et al.
patent: 4120558 (1978-10-01), Seidler
patent: 4183611 (1980-01-01), Casciotti et al.
patent: 4597628 (1986-07-01), Seidler
patent: 4618209 (1986-10-01), Sonobe
patent: 4728305 (1988-03-01), Seidler
patent: 4883435 (1989-11-01), Seidler
patent: 4900279 (1990-02-01), Dennis
patent: 5030144 (1991-07-01), Seidler
"Injectable Solderable Terminal Pins", H. P. Byrnes, IBM Tech. Disc. Bull., vol. 9, No. 4, Sep. 1966, p. 366 (439-83).
Desmond Eugene F.
North American Specialties Corporation
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