Integrated nutplate and clip for a floating fastener and method of manufacture and assembly
An inexpensive and reliable floating fastener is provided by manufacturing an integrated nutplate into the backside of the interior structural member. A retention clip engages the nutplate to capture the nut while allowing the nut to float. The integrated nutplate roughly aligns the floating nut to the axial through-hole in the structural member and provides the torque resistance required to drive the screw into the nut. The retention clip holds the nut in place and provides the axial resistance required for the lead chamfer of the screw to engage the nut and resist the axial loading on the screw during installation. The nutplate is designed to facilitate cost-effective manufacturing. The per hole cost of the integrated floating-fastener is approximately 30% of the cost of the industry standard riveted floating fastener.
1. A method of fastening structural members, comprising:
providing a first structural member having a first axial through-hole;
providing a second structural member having a second axial through-hole larger than said first axial through-hole and an integrally-formed nutplate on the backside of the second structural member near the second axial through-hole, said nutplate comprising first and second substantially parallel rails on opposite sides of the second axial-through hole, each rail having a pair of through-holes substantially perpendicular to the second axial through-hole;
positioning a nut including a threaded barrel and a base between the first and second rails on the backside of the second structural member;
inserting a U-shaped retention clip through said pair of through-holes in one said rail around the threaded barrel and extended through the pair of through-holes in the other said rail so that the base is captured by the nutplate and U-shaped retention clip allowing the nut to float;
positioning the first structural member over the front side of the second interior structural member to align the first axial through-hole to the larger second axial through-hole; and
driving a screw through said first and second axial through-holes so that a lead chamfer on the screw aligns the nut's threaded barrel and the screw, said nut base engaging said clip which resists an axial load placed on the screw and engaging said nutplate's first and second rails which resist a torque placed on the screw so that said screw is fastened into said threaded barrel by the applied torque.
2. The method of claim 1 , further comprising:
milling a block of material to form the second structural member with said pair of parallel rails defining the integrally-formed nutplate.
3. The method of claim 2 , further comprising using a 5-axis milling machine to mill the block of material, said machine including linear servo motors to effectuate milling along the X and Y axis, said parallel rails lying parallel to said X or said Y axis.
4. A method of fastening structural members, comprising:
providing a first structural member having first axial through-holes in a linear arrangement;
providing a second structural member having a plurality of second axial through-holes larger than said first through-holes in a complementary linear arrangement and an integrally-formed nutplate comprising first and second parallel rails on opposite sides of the complementary linear arrangement of second axial through-holes on the backside of the second structural member, each rail having a pair of through-holes adjacent each said second axial through-hole;
positioning a plurality of nuts each including a threaded barrel and a base between the first and second parallel rails on the backside of the second structural member over the respective second through-holes;
inserting a plurality of U-shaped retention clips through respective pairs of through-holes in one rail, around the threaded barrel and extending through the respective pair of through-holes in the opposing rail so that each said nut is captured by the parallel rails and the respective clips but allowed to float;
positioning the first structural member over the front side of the second structural member to align the first axial through-holes to the larger second axial through-holes; and
driving respective screws through said first and second axial through-holes so that a lead chamfer on the screw aligns the nut's threaded barrel and the screw, said nut base engaging said clip which resists an axial load placed on the screw and engaging said nutplate's first and second rails which resist a torque placed on the screw so that said screw is fastened into said threaded barrel by the applied torque.