Abstract: The hinge (1), designed for suspension members (2 and 3), is provided with a flexible mechanism comprising a pair of joining components (4, 5), intended to be attached to corresponding suspension members (2 and 3) and connected to each other by means of the levers (6 and 7). The levers (6 and 7) are mounted with a freedom for reciprocal motions in parallel planes around rotation axles (8,9' and 8', 9) disposed on the joining components (4, 5). The levers (6, 7) have an equal length between their rotation axles (8,9' and 8',9) whereas the locus of points, formed at a turn of the joining components (4 and 5) relative to each other by the intersection of the longitudinal axes (F1 F2 and F3 F4) of the levers (6 and 7) on a plane parallel to the plane of the lever movements, is an elliptical curve.

Abstract: A method of hardening by plastic deformation surfaces of articles shaped as continuous helical coils and having essentially round cross-section by means of deforming elements wherein said deforming elements are arranged at the opposite sides of said article for forced rotation in engagement with the surface of the material of said article, while said article is rotated about its longitudinal centerline and subjected to ultrasonic oscillations. The deforming elements are rotated in opposite directions so as to form on the surface of said article a regular microrelief in the form of an intersecting mesh-like pattern. By changing the ratio between the angular rotational velocities of the deforming elements, a microrelief of desired geometry is attained.