Adjustable oleopneumatic amortized support column, for chairs and armchairs

An oleopneumatic adjustable and deadened support column for a chair comprising:

• i) a first cylindrical body, the base of which is adapted to be connected to the base of a chair and charged with compressed air;
• ii) a second cylindrical body, co-axial with the first, and telescopically slidable therein, the upper end of said second body being adapted to be connected to the seat of a chair;
• iii) a command bar co-axial with and inside said second body, operable by lever means under said chair seat,
• iv) first slidable piston means between said first and second body, said first piston means being annularly fixed around said second body, and in sliding, sealing engagement with the inner surface of said first body;
• v) annular upper and lower floating piston means, respectively above and below said first piston means, between said first and second bodies, in sliding sealing engagement with same, said first, upper, and lower pistons defining upper and lower oil chambers between said first and second bodies;
• vi) valve means in said second body, at the level of said first piston, actuatable by said command bar to permit or interdict the flow of oil between said first and second oil chambers;
• whereby said first, upper, and lower pistons are displaceable as an ensemble when weight is placed on the seat of said chair.