Base structure in particular for a seat having an adjustable backrest

摘要

The structure comprises a tubular substantially helical element (16) which forms in succession a base contour (22) and then a member (24, 26) for connection to the floor on which the seat is placed. The upper end portion (18) of the element has extending therethrough a pivot pin (20) for connection to one of the sides of a backrest (1) and is connected by gussets (38, 40) to the connection member The opposite end portion (52) of the tube is connected to the base contour frame by gussets (30, 32). Any force exerted by the backrest on the upper end portion (18) of the tube tends to unwind the substantially helical element and is thus absorbed by the latter.