A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
A47C—CHAIRS; SOFAS; BEDS
A47C3/00—Chairs characterised by structural features; Chairs or stools with rotatable or vertically-adjustable seats
A47C3/20—Chairs or stools with vertically-adjustable seats
A47C3/28—Chairs or stools with vertically-adjustable seats with clamps acting on vertical rods
A47C3/285—Chairs or stools with vertically-adjustable seats with clamps acting on vertical rods with radially expansible clamping elements telescopically engaged in a tube or the like