Assembly for a chair with adjustable seat back and leg-rest

An assembly for a chair with adjustable seat back and leg rest comprising:

• a seat frame comprising at its lower portion at least two reinforcing cross members adapted to rest on and be fastened to a basic carrying structure, said seat frame including a first connecting strut extending between first and second sides of said seat frame;
• a seat back frame connected to a fist end of said seat frame by a hinge thereby enabling said seat back frame to rotate in relation to said seat frame, said seat back frame including a second connecting strut extending between first and second sides of said seat back frame;
• a leg-rest frame connected to a second end of said seat frame by a hinge thereby enabling said leg-rest frame to rotate in relation to said seat frame said leg-rest frame including a third connecting strut extending between first and second sides of said leg-rest frame;
• a first positioner jack including a first valve for controlling extension of said first positioner jack, said first valve being provided on an actuation device and said first positioner jack being provided between said first connecting strut and said second connecting strut;
• a second positioner jack including a second valve for controlling extension of said second positioner jack, said second valve being provided on said actuation device and said second positioner jack being provided between said first connecting strut and said third connecting strut;
• and
• an actuation lever provided on said actuation device, said actuation lever being movable between a first inactive position and second and third positions respectively cooperating with said first and second valves for altering inclination of said seat back frame and said leg-rest frame with respect to said seat frame.