Adjustable headrest for a motor vehicle seat structure or the like

Claim 1

An adjustable headrest unit for a seat structure having a backrest, the headrest unit comprising a rigid framework for supporting a padding cushion, lateral uprights adjacent to opposite sides of the framework for fixing the headrest unit to the backrest, links on said opposite sides of the framework for connecting the framework to the respective uprights, means for pivotally mounting a first end of the links on the framework, and means for pivotally mounting second ends of the links opposed to said first ends on the uprights, a fixed sector which is located adjacent to one of said sides of the framework, is fixed to the respective upright and has a peripheral portion which defines notches and has an outer convexity, a pivot pin which is part of said means for pivotally mounting the second end of the respective link on the upright and extends through the fixed sector, a vertical movable sector which is fixed to the framework and has a peripheral portion which defines notches and has an outer convexity which faces the outer convexity of the peripheral portion of the fixed sector, the notches of the two sectors being oriented in the same direction, and a spring wire fixed at one end thereof to said pivot pin, and a control element connected to an end of the spring wire opposed to said end thereof fixed to said pivot pin for controlling the displacement of said wire between a locking position of the spring wire engaged in said notches of the two sectors which face said spring wire and a position disengaged from said notches for releasing the movable sector from said fixed sector.