Circuit board inter-connection system and method
View Patent ↗An electrical inter-connection is provided such that a terminal pin which is positioned in a pin block extends through a plated through-hole in a circuit board substrate and is connected with the circuit board using a conductive bonding agent such as solder. The terminal pin is capable of inter-connection with conductive elements located on each major side of the circuit board and eliminates the need for an interference fit between the terminal pin and circuit board. The pin block includes a body and at least one stand-off. The stand-off maintains the body a sufficient distance from the circuit board substrate to enable a solder fillet to form between the plated through-hole and the terminal pin during re-flow processing. The electrical inter-connection further includes an eccentric aperture in the circuit board suitable for interference fit inter-connection with a protruding cylindrical feature such as on an electrical ground that has poor solderability characteristics. The preferred embodiment limits normal forces caused by temperature cycling, vibration, and other conditions to two areas of contact yet enables adequately low electrical contact resistance.
1. An electrical inter-connection system comprising:
a circuit board substrate including at least one aperture, said aperture being defined by a sidewall having a conductive surface; and
a conductive body having at least one protrusion extending from a base, said protrusion engaging two spaced-apart generally flat surfaces of said sidewall upon inserting said protrusion in said aperture, and once inserted, said protrusion being seized within said aperture at said two spaced-apart portions with an interference fit between said protrusion and said two spaced-apart portions,
wherein said aperture has an eccentric shape,
wherein said aperture is shaped as a slot having a length and a width,
wherein the difference between said slot width and said protrusion diameter is between 1.5% and 20% of said slot width, and
wherein the electrical inter-connection system is solderless.
2. An electrical inter-connection system as recited in claim 1 , wherein said protrusion has a generally cylindrical shape.
3. An electrical inter-connection system as recited in claim 2 , wherein said circuit board substrate has a first surface and opposing second surface, said aperture extending between said first and second surfaces.
4. An electrical inter-connection system as recited in claim 1 , wherein said protrusion has a draft angle between 1 and 3 degrees.
5. An electrical inter-connection system as recited in claim 1 wherein the circuit board substrate is an epoxy glass laminate and wherein the conductive body is a cast aluminum body.
6. A solderless electrical inter-connection system comprising:
a circuit board substrate including at least one eccentric aperture defined by a sidewall having a conductive surface, the at least one eccentric aperture having a wide portion and a narrow portion, the narrow portion defining two spaced-apart flat surfaces, and
a conductive body having at least one generally cylindrical protrusion extending from a base, the protrusion engaging two spaced-apart flat surfaces of the at least one eccentric aperture upon inserting the protrusion in the aperture, and once inserted, the protrusion being seized within said aperture at the two spaced-apart flat surfaces with an interference fit between the protrusion and the two spaced-apart flat surfaces of the at least one eccentric aperture,
wherein the generally cylindrical protrusion has a diameter and wherein the difference between the diameter of the generally cylindrical protrusion and the width of the slot is between 1.5% and 20% of the width of the slot, and
wherein the length of the slot is generally at least 34% larger than the width of the slot to prevent the protrusion being seized within said aperture except at the two spaced-apart flat surfaces which provide an interference fit between the protrusion and the two spaced-apart flat surfaces of the at least one eccentric aperture.
7. The electrical inter-connection system as defined in claim 6 , wherein the at least one eccentric aperture is shaped as a slot having a length and a width.
8. The electrical inter-connection system as defined in claim 7 wherein the protrusion has a draft angle between 1 and 3 degrees.