SBIR-STTR Award

Enduralock proposes a project to develop the first mechanically locking, high vibration resistant fasteners in sizes of No. 4 - No. 10. Missiles, launch vehicles, and their satellite payloads undergo tremendous vibration. Safety wire is currently used to try to prevent fasteners from loosening, but this is labor intensive, and the wire is subject to breakage. Enduralock’s proposed solution would provide for more security in the mounting of electronic components and would also allow for the elimination of safety wire within missiles and satellites. This would dramatically reduce the time and cost of production, while also providing for a significant improvement in reliability. For fastener sizes of ¼” and greater, Enduralock currently offers the first mechanically locking, high vibration resistant permanent fasteners, that for maintenance are reversible and reusable with a standard hex socket. They are ideal for critical applications, as the fasteners remain locked even with total loss of preload. Enduralock fasteners survived 10x the aerospace vibration requirement for a self-locking nut, and reusability has been demonstrated to 250 cycles. Enduralock has obtained 2 new National Aerospace Standards, and it won a NASA competition last year. The challenge, however, is to miniaturize these fasteners for use in missiles and satellites.

Enduralock’s proposal is to develop the first mechanically locking, high vibration resistant fastener, that is reversible and reusable with a standard hexagonal socket in sizes of No.4 – No.10. A requirement of this research and development is that the fastener will remain mechanically locked even with loss of preload (clamping force), so that the fastened assembly will be unaffected by the extreme environmental temperatures (and the corresponding thermal expansion and contraction of the fastener components) experienced in space. The vibration resistance of the proposed fasteners will be comparable to a larger variant of the proposed technology, which was previously shown to survive 10 times the aerospace vibration requirement (NAS1312-7). The project will include design and finite element analysis to optimize the fasteners for performance and for manufacturability. This will be followed by qualification testing of the fasteners. Enduralock also proposes research and development of a novel fastener assembly automation process using a robotic arm and development of ultrasound preload measurement technology for reliable installation of fasteners in a space environment. The final deliverable of this project will be a fastener that could eventually replace fasteners that are currently safety-wired together in missiles, commercial satellites, space vehicles, space structures, and aircraft.