Resistance welding fastener, apparatus and methods
An apparatus and method for fastening dissimilar materials like steel, plastic and aluminum. A resistance welding fastener having multiple layers may be used with or without a sealant. The fastener may be used to form an aluminum covered steel laminate via a hemming pattern of attachment. The fastener may have a solid shaft or have an extended reach and have features for interacting with the welding electrode. A variety of electrode tips may be employed to cooperate with the fastener.
1. A fastener for fastening a first material to a second material using electrical resistance welding, comprising:
a cap having an electrode receiving surface and an underside portion opposite the electrode receiving surface,
wherein the electrode receiving surface includes a concave surface,
wherein the concave surface is configured to receive a convex portion of an electrode; and
a shaft extending from the underside portion of the cap and having an end distal to the cap,
the fastener being electrically conductive and, when placed in a stack including the first and second materials and subjected to an electrical potential applied across the stack, capable of conducting an electrical current that passes through the stack,
the electrical current causing resistive heating and welding to the second material at the end distal to the cap, and
the first material being captured between the cap and the second material after the end is welded to the second material.
2. The fastener of claim 1 , further comprising a structure with:
at least one non-ferrous material component;
a plurality of ferrous metal components;
the fastener welded to at least one of the plurality of ferrous metal components by electrical resistance welding forming a first weld, the shaft extending through the non-ferrous material and welding to a first of the plurality of ferrous metal components at a first location on a first side thereof,
a second electrical resistance weld between the first ferrous metal component and a second ferrous metal component of the plurality of ferrous metal components,
the second electrical resistance weld located proximate to the first location but on a second, opposite side of the first ferrous component,
the at least one non-ferrous material component captured between the cap and the first ferrous component.
3. The fastener of claim 2 , wherein the structure having the at least one non-ferrous material component is a sheet of an aluminum alloy.
4. The fastener of claim 3 , wherein the structure having the first of the plurality of ferrous metal components is a steel sheet.
5. The fastener of claim 4 , wherein the structure having the second of the plurality of ferrous metal components is a second fastener.
6. The fastener of claim 1 , wherein the concave surface of the electrode receiving surface includes a first radius of curvature and the convex portion of the electrode includes a second radius of curvature.
7. The fastener of claim 6 , wherein the first radius of curvature is greater than the second radius of curvature.
8. The fastener of claim 6 , wherein the first radius of curvature is equal to the second radius of curvature.
9. The fastener of claim 6 , wherein the first radius of curvature is substantially similar to the second radius of curvature.
10. The fastener of claim 6 , wherein the first radius of curvature is 1 inch to 6 inches.
11. The fastener of claim 10 , wherein the second radius of curvature is 3 mm to 8 mm.
12. A fastener, comprising:
a cap having an electrode receiving surface and an underside portion opposite the electrode receiving surface,
wherein the electrode receiving surface includes a concave surface,
wherein the concave surface is configured to receive a convex portion of an electrode; and
a shaft extending from the underside portion of the cap and having an end distal to the cap.
13. The fastener of claim 12 , wherein the concave surface of the electrode receiving surface includes a first radius of curvature and the convex portion of the electrode includes a second radius of curvature.
14. The fastener of claim 13 , wherein the first radius of curvature is equal to the second radius of curvature.
15. The fastener of claim 13 , wherein the first radius of curvature is substantially similar to the second radius of curvature.
16. The fastener of claim 13 , wherein the first radius of curvature is 1 inch to 6 inches.
17. The fastener of claim 13 , wherein the second radius of curvature is 3 mm to 8 mm.