Method of fastener assembly for preloading a joint

Abstract

A method and fastener assembly for preloading a joint wherein a pin having a shank and a head at one end is disposed with the shank portion passing through aligned apertures of a plurality of workpieces to be joined. The shank portion of the pin extends beyond the surface of the workpiece and is provided with an irregular surface configuration. A deformable collar having an initially smooth surfaced internal bore is disposed about the pin and snugged against the adjacent workpiece by a removably positioned means placed in abutting relationship against the free surface of the collar to lightly clamp the joint assembly together to remove free play in the joint. The collar is radially inwardly deformed by a crimping tool so that the initially smooth surfaced internal bore of the collar is deformed to assume a configuration complimentary to the irregular surface configuration of the pin shank and upon continual application of the crimping force an axial elongation of the collar and the shank of the pin is effected to provide a predetermined tension or preload on the joint assembly. After the collar has been deformed, the means to snug the joint together initially is removed.