Abstract: A bolt shank and washer have contiguous respective elliptical and circular surfaces that interact to impart an undulated axial distortion to the washer in a circumferentially running sinusoidal way, so that the washer acts in spring-like fashion to lock the bolt in its tightened position. The elliptical surface is tapered outwardly toward the bolt head to give an increased spring constant with increased tightening.

Abstract: An epicyclic speed reducing mechanism employs, as torque transmitting elements, a series of rolling elements which are constrained to travel along a substantially trochoidal path defined by means of complementary or conjugate surface regions formed on the driving and driven members. The invention is applicable to single or multiple stage speed reducers, and may be of the counterweighted or counterbalanced variety, the latter including a constant velocity coupling operating between an orbiting and rotating element and a further element. In the disclosed embodiments, the rolling elements may be either balls or rollers, and the surface regions may be conjugate epitrochoidal and hypotrochoidal grooves.