Chair for user sitting

Abstract

Chair for user sitting, which comprises a seat provided with a support portion and with a seat portion, to which a back is hinged. The seat comprises two elastic leaf springs, each of which has a central portion, fixed to the support portion, and two lateral wings, which are fixed to the seat portion and are extended projecting from the central portion, moving away from the back, tilted with respect to an axis orthogonal to the seat surface of said seat portion. The lateral wings are configured for being elastically bent between a first position, in which they are placed tilted by a rest angle, and a second position, in which they are placed tilted by an operative angle smaller than the rest angle.

1 . A chair for user sitting, said chair comprising:
 a support structure ( 2 ), which is intended to be placed in abutment against a ground;   a seat ( 3 ), which comprises, in a single body, a support portion ( 31 ), which is mounted above said support structure ( 2 ), and a seat portion ( 32 ), which defines a seat surface (γ) in order to receive a user in seated position;   a back ( 4 ), which is extended along a main extension direction (Y), substantially vertical, between an upper end ( 4 ′) and an opposite lower end ( 4 ″), and is hinged to the support portion ( 31 ) of said seat ( 3 ) around a hinging axis (R), at a hinging point (I);   
       wherein said back ( 4 ) is rotatable around said hinging axis (R) between at least one rest position (A), in which said back ( 4 ) is placed substantially vertical, and at least one reclined position (B); 
       wherein said back ( 4 ) is mechanically connected to the seat portion ( 32 ) of said seat ( 3 ), at a connection point (C), in order to move said seat portion ( 32 ), along at least one translation direction (T) substantially orthogonal to the main extension direction (Y) of said back ( 4 ), following the rotation of said back ( 4 ) around said hinging axis (R); 
       wherein said hinging point (I) is placed in proximity to the lower end ( 4 ″) of said back ( 4 ), and said connection point (C) is placed above said hinging point (I), between said hinging point (I) and the upper end ( 4 ′) of said back ( 4 ); 
       wherein said seat ( 3 ) comprises elastic return elements ( 5 ), which are integral with said support portion ( 31 ) and said seat portion ( 32 ) of said seat ( 3 ) and comprise at least two elastic leaf springs ( 50 ), each of which comprises a central portion ( 51 ), which is fixed to said support portion ( 31 ), and two lateral wings ( 52 ), which are extended projecting from opposite sides of said central portion ( 51 ) and are extended up to respective ends ( 52 ′) fixed to said seat portion ( 32 ); 
       wherein the lateral wings ( 52 ) of said leaf springs ( 50 ) is extended starting from said central portion ( 51 ), moving away from said back ( 4 ), and being tilted with respect to an axis (N) substantially orthogonal to the seat surface of said seat portion ( 32 ); 
       wherein said lateral wings ( 52 ) are configured for being elastically bent following the translation of said seat portion ( 32 ) along said translation direction (T), and for exerting an elastic return force on said seat portion ( 32 ) in order to force said back ( 4 ) to rotate towards said rest position (A); 
       wherein said lateral wings ( 52 ) are flexible between:
 a first position, in which said lateral wings ( 52 ) are placed tilted with respect to said axis (N) by a rest angle (α), and 
 a second position, of bending, in which said lateral wings ( 52 ) are placed tilted with respect to said axis (N) by an operative angle (β), which is smaller than said rest angle (α). 
 
     
     
         2 . The chair of  claim 1 , further comprising at least one connecting rod ( 6 ), which is pivoted to said back ( 4 ) and to said seat portion ( 32 ) in order to kinematically connect said back ( 4 ) to the seat portion ( 32 ) of said seat ( 3 ) at said connection point (C). 
     
     
         3 . The chair of  claim 2 , wherein said back ( 4 ) is provided with a first housing seat and said seat portion ( 32 ) is provided with a second housing seat, and said connecting rod ( 6 ) is partially housed in the first housing seat of said back ( 4 ) and in the second housing seat said seat portion ( 32 ). 
     
     
         4 . The chair of  claim 1 , wherein said back ( 4 ) is provided with:
 a main portion ( 41 ), substantially vertical, which is extended along said main extension direction (Y) between said upper end ( 4 ′) and a bent portion ( 42 ); and   a connection portion ( 43 ), which is placed transverse to said main portion ( 41 ) and is extended between said bent portion ( 42 ) and the lower end ( 4 ″) of said seat ( 4 );   
       wherein said hinging point (I) is placed on the connection portion ( 43 ) of said back ( 4 ), and said connection point (C) is placed on the main portion ( 41 ) of said back ( 4 ). 
     
     
         5 . The chair of  claim 1 , wherein the support portion ( 31 ) of said seat ( 3 ) is placed below said seat portion ( 32 ), towards said support structure ( 2 ), and that said elastic return elements ( 5 ) are interposed between said support portion ( 31 ) and the seat portion ( 32 ) of said seat ( 3 ). 
     
     
         6 . The chair of  claim 1 , wherein the support portion ( 31 ) of said seat ( 3 ) is extended along a main extension direction (X), between a rear end ( 31 ′), at which said back ( 4 ) is hinged, and an opposite front end ( 31 ″); wherein said elastic return elements ( 5 ) comprise a rear leaf spring ( 50 ′), fixed at the rear end ( 31 ′) of the support portion ( 31 ) of said seat ( 3 ), and a front leaf spring ( 50 ″), fixed at the front end ( 31 ″) of the support portion ( 31 ) of said seat ( 3 ). 
     
     
         7 . The chair of  claim 6 , wherein said rear leaf spring ( 50 ′) is placed tilted with a first rest angle (α′) with respect to said axis (N), and that said front leaf spring ( 50 ″) is placed tilted with a second rest angle (α″) with respect to said axis (N), and said second rest angle (α″) is greater than said first rest angle (α′). 
     
     
         8 . The chair of  claim 6 , wherein said seat portion ( 32 ) is extended, parallel to said main extension direction (X) of said support portion ( 31 ), between a rear side ( 32 ′), fixed to said back ( 4 ), and an opposite front side ( 32 ″); 
       wherein said front leaf spring ( 50 ″) is placed with said lateral wings ( 52 ) fixed at the front side ( 32 ″) of said seat portion ( 32 ). 
     
     
         9 . The chair of  claim 1 , wherein the support portion ( 31 ) of said seat ( 3 ) is constrained to said support structure ( 2 ) and integral with the latter for movements of said seat portion ( 32 ) along said translation direction (T). 
     
     
         10 . The chair of  claim 1 , wherein each said elastic leaf spring ( 50 ) defines four virtual hinging points, including two first virtual hinging points between the central portion ( 51 ) of said elastic leaf spring ( 50 ) and the support portion ( 31 ) of said seat ( 3 ), and two second virtual hinging points between the seat portion ( 32 ) of said seat ( 3 ) and the lateral wings ( 52 ) of the corresponding said leaf spring ( 50 ).