Abstract: A screw-type fastening device including a male threaded element such as a bolt and a female threaded element such as a nut in which each element contains continuous helical root and crest disposed therein wherein the root and crest include cone-shaped crests and cone-shaped roots at an angle of about 45.degree. to 90.degree., respectively, external and internal chevron-shaped slots at angles of about 135.degree. to 225.degree., respectively, and three pairs of parallel load flanks, respectively, for easily releasing the threaded elements without abrasion and protecting them from self-loosening from each other.

Abstract: A screw-type fastening device including a male threaded element such as a bolt and a female threaded element such as a nut in which each element contains a continuous helical root and crest disposed therein wherein the root and crest include V-shaped crests and V-shaped roots at an angle of 45.degree., respectively, external and internal chevron-shaped slots at angles of 90.degree., respectively, and three pairs of parallel load flanks, respectively, for easily releasing the threaded elements without abrasion and protecting them from self-lossensing from each other.