SBIR/STTR Award attributes
Enduralock’s proposal is to improve the reliability and reduce the need for maintenance of the ground support equipment for the B-1, B-2, and KC-135 aircraft. This is through the development of its mechanically locking, high vibration resistant fasteners as component substitutions on the equipment. Ground support equipment such as generators and compressors are subject to high vibration, which can lead to fasteners loosening and the resultant need for maintenance of the equipment. Conventional fasteners with self-locking nuts and bolts, are not reliable when used to assemble components of systems exposed to very high vibration. A small loss in preload, specifically in systems exposed to high vibration, results in a failure of the bolted joint. It is imperative that for systems undergoing high vibration, a permanently locking fastener technology be used for the system assembly. The disadvantage of the use of conventional permanently locking fasteners is that for maintenance they need to be cut out and then replaced. The ideal fastener for use in a high vibration environment would be a mechanically locking fastener that is easy to apply and easy to remove, with the cost benefit of reuse of the fasteners during maintenance operations on the equipment. Fasteners used in critical applications are often safety-wired together to reduce the chance of loosening with vibration, which is very labor-intensive and therefore costly. A mechanic can typically safety-wire 10 fasteners per hour at an hourly labor rate of $150. In that same period of time, over 300 of Enduralock’s Silver Lock fasteners could be installed. Enduralock’s Tidal Lock Fastener and its Locking Header Bolt technologies allow for permanence in the assembled joint due to their mechanical lock. They also provide for easy reversibility and reusability with a standard hex socket which disengages the mechanical lock. In vibration testing, Enduralock fasteners survived 10x the aerospace requirement without failure. Reusability has been demonstrated to 250x. If bolt elongation occurs over time, the fastener can be easily retensioned with a standard socket. They remain locked even with loss of preload (clamping force), so they are unaffected by thermal changes in the equipment or the environment causing expansion or contraction of the bolts with resultant loss of preload. In summary, by developing and testing Enduralock’s fasteners as substitution components for B-1, B-2, and KC-135 ground support equipment, the reliability of the equipment will be improved, and less maintenance of the equipment will be required. This will result in improved maintenance times for the B-1, B-2, and KC-135 aircraft.
