Hi-Lok® Two-Part Frangible Fastener
Hi-Lok® is a simple two-part fastener engineered to achieve in one all-purpose system the design features suiting many of today's aerospace assembly needs. Consistent torque on each fastener installed is achieved through the integrated functions of the system working together. A carefully regulated breakoff groove in the self-locking Hi-Lok® collar provides uniform preload values by separating when the correct torque level is reached. This controlled preload of each Hi-Lok® in the structure improves the fatigue life of the airframe significantly when compared to other fastening systems, including swaged collar type. The Hi-Lok® pin is held stationary by the installation tool while the collar rotates. Progressive tightening takes place as torque is applied. At the designed torque level built into the Hi-Lok® collar, the hex portion of the collar is sheared off automatically by the driving tool.
Hi-Lok® cannot be over-torqued; the collar's automatic breakoff design assures this and eliminates the need for torque inspection. As a highly efficient and dependable system.
As a versatile fastener, Hi-Lok® matches the best qualities of a bolt/nut or pin swaged collar combination. Tooling is easily adaptable to large scale production with high speed equipment and automatic collar feed attachments that handle up to 200 collars, affording installation rates of up to 45 fasteners per minute in some cases. The compactness of the Hi-Lok® tooling is in a class by itself when installation means reaching into hidden areas and next-to-impossible places. In fact, Hi-Lok® is often the only one utilizing high-speed driving equipment that is approved and qualified for use in many difficult access conditions. An extensive range of installation tools satisfies standard, offset and extended offset, 200, 900 and 1800 requirements. The Hi-Lok® design does more with less, solving weighty problems and delivering high fatigue resistance without sacrificing strength. The lightweight Hi-Lok® collar further contributes to weight-saving when compared to conventional nut and bolt systems of equal strength characteristics. Manufactured in a wide range of sizes and material combinations, in terms of versatility the Hi-Lok® system offers engineering designers a ready solution to a variety of assembly problems.