Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – Distinct contact secured to panel circuit
Reexamination Certificate
1997-11-21
2001-01-30
Yan, Ren (Department: 2854)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
Distinct contact secured to panel circuit
C439S876000, C228S255000, C228S246000, C228S056300
Reexamination Certificate
active
06179631
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrical contact, and more particularly to an electrical pin contact for mounting on a printed circuit board.
2. Description of Related Art
Electrical pin contacts are typically mounted to a printed circuit board for establishing electrical interconnections to the circuitry of the board. For example, one or more contacts can be mounted to a circuit board to provide test pin connections that can be probed for testing or troubleshooting the board. Pin contacts can also provide an interface for an electrical connector or other socket-type device to interconnect a board to other electronic components.
Electronic components, including pin contacts, are generally configured for mounting on a printed circuit board as either a surface mount component or a through-hole component. A surface mount component includes leads that are soldered directly to surface mount pads provided on the outer surfaces of the circuit board. Conventionally, the component leads are pressed into a layer of solder paste, which includes both solder and flux, deposited on the pads. Once the surface mount components are assembled to the circuit board, the board and components are heated to reflow the solder and form solder joints between the leads and pads.
A through-hole component includes elongated leads that are inserted into plated-through holes extending through the circuit board. Conventionally, the component leads are soldered to the plated-through holes using a wave soldering process that fills the holes with solder to electrically and mechanically connect the leads to the holes.
When a printed circuit board includes both surface mount components and through-hole components, separate manufacturing steps are typically required to solder the various components to the board. Generally, the surface mount components are first assembled and reflow soldered to the board with the through-hole components being subsequently assembled and wave soldered to the board. In addition to increasing the number of process steps, this process can impact the overall reliability of the board since the surface mount components and their solder joints are subjected to the thermal shock of the wave soldering process.
Surface mount pin contacts have been proposed for surface mount applications so that the pin contacts may be reflow soldered at the same time as the surface mount components. Surface mount pin contacts, however, tend to have less structural integrity than a through-hole contact. Additionally, the solder joint between the surface mount pad and the contact is at substantial risk to fail, since the contact typically includes no support structure that would distribute forces applied to the contact away from the solder joint. Surface mount electrical contacts used as test pins are particularly prone to structural and solder joint failures since they are typically subjected to relatively large forces when probed, grasped and interconnected during testing on a board. The lack of support structure also makes it difficult to maintain a surface mount contact precisely positioned on a circuit board during the assembly process.
It is an object of the present invention to provide an improved electrical contact and a method of mounting the electrical contact in a plated-through hole on a printed circuit board.
SUMMARY
The present invention is an electrical contact having the structural integrity of a through-hole component with the capability of being soldered to a printed circuit board using a surface mount reflow process. The contact includes a pin that is insertable through a plated-through hole in the printed circuit board. A solder preform supported on the pin may be surface mount reflowed to form a solder joint between the contact and the plated-through hole.
In one illustrative embodiment of the invention, the electrical contact comprises a base including opposing first and second ends, a first conductive pin attached to the first end of the base, and a second conductive pin attached to the second end of the base. The first conductive pin is insertable into the plated-through hole. The contact also comprises at least one solder preform supported on the first conductive pin that is to be disposed between the first end of the base and the printed circuit board when the first conductive pin is inserted through the plated-through hole.
In another illustrative embodiment of the invention, the electrical contact comprises a base, a first conductive pin, a second conductive pin, and at least one solder preform supported on one of the first and second conductive pins. Each of the first and second conductive pins is insertable into the plated-through hole with the solder preform to be disposed between the base and the printed circuit board when the one of the first and second conductive pins is inserted through the plated-through hole. The base includes a central portion, a first flange with first and second ends and a second flange with first and second ends. The second end of the first flange is attached to a first end of the central portion and the first end of the second flange is attached to a second end of the central portion. The first conductive pin is attached to the first end of the first flange and the second conductive pin is attached to the second end of the second flange.
In a further illustrative embodiment of the invention, a method is provided for mounting an electrical contact to a printed circuit board having a plated-through hole. The method comprises steps of providing an electrical contact that includes a base, a first conductive pin attached to a first end of the base, a second conductive pin attached to a second end of the base, and a solder preform supported on the first conductive pin; inserting the first conductive pin into the plated-through hole of the printed circuit board so that the solder preform is disposed between the base and the printed circuit board; and reflowing the solder preform into the plated-through hole along the first conductive pin to form a solder joint between the electrical contact and the plated-through hole.
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Downes Stuart D.
Merrill Leonard A.
EMC Corporation
Wolf Greenfield & Sacks P.C.
Yan Ren
LandOfFree
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