Patent ID: 8316737

Claim:
An electric clamping arrangement for use in combination with the adjustable steering column of an automotive vehicle including a steering shaft rotatably mounted about a steering axis in a body tube, said steering column being mounted in a support assembly including a fixed support member made up of two uprights and a connecting member, and a movable support member in which said body tube is arranged, said clamping arrangement comprising: (a) a clamping rod extending along a clamping axis that is substantially normal to a vertical steering plane passing through said steering axis and passing through said two uprights of said fixed support member; and (b) immobilizing means mounted on said clamping rod for immobilizing said body tube in a locked position relative to said fixed support member, said immobilizing means including; (1) a fixed cam rotationally fixed with respect to said clamping axis and having a rolling path, (2) a movable cam rotationally movable with respect to said clamping axis and having a rolling path, and (3) at least one ball arranged for rolling contact between said fixed and movable cam rolling paths; (4) each of said rolling paths having an escape slope for said ball with respect to the corresponding cam, whereby upon rotation said movable cam with respect to said fixed cam according to a given rotational direction, said fixed cam and said movable cam are displaced relative to each other as a function of said rotational direction, thereby to produce one of said locked and unlocked conditions of said steering column: (5) the escape slopes of said rolling paths having a varying value less than a value linked to the friction coefficient of said rolling member; (6) each of said rolling paths extending along a curve having a radius varying with respect to said clamping axis, such that the distance between said ball and said clamping axis varies along said rolling paths; (c) said movable cam being axially displaceable relative to said fixed cam as a function of the rotation of said movable cam and the position of said ball with respect to said clamping axis and said rolling path escape slopes.