Steering mechanism for bicycles, motorcycles and the like

A steering mechanism for bicycles, motorcycles and the like, comprising a tubular portion integral with the frame of the vehicle, and a cylinder extending coaxially in said tubular portion and telescopically attached on one end to the extension of the handlebar and at the other end to the fork of the wheel to be steered, between said tubular portion and said cylinder there being interposed two axially spaced apart, upper and lower bearing assemblies each comprising concentric, inner and outer races defining therebetween an annular groove having a square cross section, in said groove there being seated and guided a plurality of cylindrical rollers that are alternately inclined in opposite directions to thereby result in pairs of said cylindrical rollers positioned perpendicular to one another and inclined with respect to the axis of the steering mechanism, said inner race of each said bearing assembly being provided with an axial extension the upper one of which is coupled to said tubular portion and the lower one of which is coupled to said cylinder, while said outer race of each said bearing assembly is forcedly seated and coupled to upper and lower supporting elements, the upper one of which is coupled to said cylinder and the lower one of which is coupled to said tubular portion.