Method of forming a tubular rivet in fastening relation to a plurality of laminates

Claim 1

A method for forming a tubular rivet in fastening relation to a plurality of laminates one or both of which is tapered in thickness and through which laminates a rivet hole extends having first and second countersinks the axes of which are at small angles to the axis of said rivet hole, the method comprising the steps of: providing in said hole a tubular rivet at least one end of which is unformed and the other end of which has a partially formed conical rivet head; providing a forming mandrel having a head presenting a first conical forming surface adjacent said unformed end and having a shaft extending through the lumen of said rivet; providing an annular anvil having a central bore through which said shaft extends and presenting a second conical forming surface to said partially formed conical rivet head; said shaft being bendable adjacent said mandrel head and said bore of said anvil being tapered to permit tilting of said anvil relative to said shaft; and forcefully moving said mandrel head and said anvil toward one another so as to flare said one end and further flare said other end to form first and second conical rivet heads the axes of which are substantially coaxial with said axes of said countersinks.

Claim 2

A method for forming a tubular rivet in fastening relation to a plurality of laminates one or both of which is tapered in thickness and through which laminates a rivet hole extends having first and second countersinks the axes of which are at small angles to the axis of said rivet hole, the method comprising the steps of: providing in said hole a tubular rivet at least one end of which is unformed and the other end of which has a partially formed conical rivet head; providing a forming mandrel having a head presenting a first conical forming surface adjacent said unformed end and having a shaft extending through the lumen of said rivet; providing an annular anvil having a central bore through which said shaft extends and presenting a second conical forming surface to said partially formed conical rivet head; said shaft being bendable adjacent said mandrel head and said bore of said anvil being tapered to permit tilting of said anvil relative to said shaft; and forcefully moving said mandrel head and said anvil toward one another so as to flare said one end and further flare said other end to form first and second conical rivet heads the axes of which are substantially coaxial with said axes of said countersinks.