Abstract: A back rest for a seat wherein the back rest includes a support member having first and second edge surfaces, a central plate between the edge surfaces, a first side member coupling the central plate to the first edge surface, and a second side member coupling the central plate to the second edge surface. The central plate of the support member is recessed from the first and second end surfaces to define a cavity. The back rest further includes a plurality of protrusions extending from the central plate and into the cavity. Additionally, the back rest includes a lordosis support having first and second ends coupled to the plurality of protrusions, at least one of the first and second lordosis support ends being coupled to the plurality of protrusions for movement relative to the support member. The lordosis support is adapted to bow upon displacement of one of the first end and the second end thereof toward one another thereby forming a curvature.

Abstract: Arching mechanism, for instance for backrests of seats, medical or orthopaedic apparatus or casings and the like, with a pressure element wherein at least one traction element connected with a tensioning mechanism engages, which, when the mechanism is actuated can produce bulging by preserving a relative elevation of apex of the convexity; the arching mechanism can comprise a frame with inserted pressure elements actuatable by adjusting device(s), whereby frame segments are length-variable pressure elements; traction elements provided with tensioning mechanism can engage a slitted, overlapping or bellows-like bulging body for the opening and closing of these areas, which produces a curving of the bulging body in a predetermined direction or directions.

Abstract: Arching mechanism, for instance for backrests of seats, medical or orthopaedic apparatus or casings and the like, with a pressure element wherein at least one traction element connected with a tensioning mechanism engages, which, when the mechanism is actuated can produce bulging by preserving a relative elevation of apex of the convexity; the arching mechanism can comprise a frame with inserted pressure elements actuatable by adjusting device(s), whereby frame segments are length-variable pressure elements; traction elements provided with tensioning mechanism can engage a slitted, overlapping or bellows-like bulging body for the opening and closing of these areas, which produces a curving of the bulging body in a predetermined direction or directions.

Abstract: Arching mechanism, for instance for backrests of seats, medical or orthopaedic apparatus or casings and the like, with a pressure element wherein at least one traction element connected with a tensioning mechanism engages, which, when the mechanism is actuated can produce bulging by preserving a relative elevation of apex of the convexity; the arching mechanism can comprise a frame with inserted pressure elements actuatable by adjusting device(s), whereby frame segments are length-variable pressure elements; traction elements provided with tensioning mechanism can engage a slitted, overlapping or bellows-like bulging body for the opening and closing of these areas, which produces a curving of the bulging body in a predetermined direction or directions.

Abstract: Arching mechanism, for instance for backrests of seats, medical or orthopedic apparatus or casings and the like, with a pressure element wherein at least one traction element connected with a tensioning mechanism engages, which, when the mechanism is actuated can produce bulging by preserving a relative elevation of apex of the convexity; the arching mechanism can comprise a frame with inserted pressure elements actuatable by adjusting device(s), whereby frame segments are length-variable pressure elements; traction elements provided with tensioning mechanism can engage a slitted, overlapping or bellows-like bulging body for the opening and closing of these areas, which produces a curving of the bulging body in a predetermined direction or directions.

Abstract: Arching mechanism, for instance for backrests of seats, medical or orthopaedic apparatus or casings and the like, with a pressure element wherein at least one traction element connected with a tensioning mechanism engages, which, when the mechanism is actuated can produce bulging by preserving a relative elevation of apex of the convexity; the arching mechanism can comprise a frame with inserted pressure elements actuatable by adjusting device(s), whereby frame segments are length-variable pressure elements; traction elements provided with tensioning mechanism can engage a slitted, overlapping or bellows-like bulging body for the opening and closing of these areas, which produces a curving of the bulging body in a predetermined direction or directions. (FIG. 1).