Abstract: A pair of generally coaxial mutually rotatable cylindrical outer ring members (34, 36) are held in spaced apart relationship by three parallelogram shaped relatively thin, flexible, flat planar spring elements (48, 50, 52) which are substantially inextensible in length and are joined to the inside of the outer ring members and held in position by arcuate inner ring segments (38, 40 . . . 46), three for each outer ring member, which respectively span an arc of substantially 120.degree.. The parallelogram shape of the spring elements (48, 50, 52) provides a slanted interconnection between the outer ring members (34, 36). The direction of slant, moreover, determines in which direction the spring elements (48, 50, 52) can flex or bend unidirectionally to relieve the compression stress imparted thereto by any mutual angular rotation of the outer ring members (34, 36).

Abstract: A belt for transmitting power from a cogged driving member to a cogged driven member such as a pair of wheel sprockets. The belt has inflexible teeth spaced along the direction of its travel. Each of the teeth have a longitudinal axis transverse to the direction of belt travel. The belt also includes substantially inextensible fasts spaced transversely to the direction of belt travel. The fasts extend in the direction of belt travel adjacent to the teeth and are looped around preselected numbers of the teeth.