Abstract: Extended fatigue endurance and high pre-load are achieved in a structural blind fastener by combining the best features of screw type and pull type blind fasteners. We replace fatigue critical details from the shear plane with close tolerance, slip fit, core bolt and outer bolt shanks to obtain the desired structural load paths while retaining anchoring features of screw type fasteners to introduce adequate pre-load. These fasteners are compatible with currently available blind bolt insertion tooling.

Abstract: We achieved extended fatigue endurance and high pre-load in a structural blind fastener by combining the best features of screw type and pull type blind fasteners. We replaced fatigue critical details from the shear plane with close tolerance, slip fit, core bolt and outer bolt shanks to obtain the desired structural load paths while retaining anchoring features of screw type fasteners to introduce adequate pre-load. Our fasteners are compatible with currently available blind bolt insertion tooling. The present invention pertains to a lightweight version of the structural blind fastener wherein we set the backside anchor collar with matching threads that engage between the outer sleeve bolt and inner core bolt.