Chair for the sitting of a user and method of mounting said chair

Abstract

Chair comprising a support structure provided with a first housing seat having a first non-circular opening, and with a support element, which is mechanically connected to the support structure and is provided with a second housing seat, which is aligned and communicating with the first housing seat. The chair also comprises a removable connection system having a locking pin provided with a non-circular head, which engages the first housing seat and the second housing seat and is rotatable between a release position, in which it releases the support element from the support structure, and a constraint position, in which the support element is constrained to the support structure. The locking pin comprises an elastic retention element which is elastically engaged in a first retention recess of the first housing seat when the locking pin is in the constraint position, in order to retain the locking pin therein.

1 . A chair for the sitting of a user, said chair comprising:
 a support structure ( 2 ), which comprises a support base ( 21 ), which is intended to be placed in abutment against a ground, and a seat ( 210 ), which is mounted above said support base ( 21 ) and is intended to support a user in seated position;   wherein said support structure ( 2 ) is provided with at least one first housing seat ( 20 ) provided with a first opening ( 200 );   at least one support element ( 3 ), which is mechanically connected to said support structure ( 2 ) and is selected from among a back ( 31 ) and a pair of arms ( 32 ), in order to respectively support a back or an arm of the user;   wherein said at least one support element ( 3 ) is provided with a second housing seat ( 30 ), which is aligned and communicating with the at least one first housing seat ( 20 ) of said support structure ( 2 ), when said at least one support element ( 3 ) is mounted on said support structure ( 2 );   a removable connection system ( 4 ), which is placed as a mechanical connection between said support structure ( 2 ) and said at least one support element ( 3 ) and comprises a locking pin ( 41 ) provided with a non-circular head ( 410 ); wherein said locking pin ( 41 ) engages said at least one first housing seat ( 20 ) and said second housing seat ( 30 ) and is rotatable in a constraint sense, around a rotation axis (R), between at least one release position (B), in which said locking pin ( 41 ) releases said at least one support element ( 3 ) from said support structure ( 2 ), and a constraint position (C), in which said at least one support element ( 3 ) is constrained to said support structure ( 2 );   
       wherein said locking pin ( 41 ) comprises an elastic retention element ( 411 ), and 
       wherein said support structure ( 2 ) defines, in said at least one first housing seat ( 20 ), a first retention recess ( 21 ′), in which said retention element ( 411 ) is elastically engaged when said locking pin ( 41 ) is in said constraint position (C), in order to retain said locking pin ( 41 ) in position, by impeding said locking pin ( 41 ) from rotating around said rotation axis (R). 
     
     
         2 . The chair of  claim 1 , wherein said support structure ( 2 ) defines, in said at least one first housing seat ( 20 ), a second retention recess ( 21 ″), which is engageable by said elastic retention element ( 411 ) when said locking pin ( 41 ) is in said at least one release position (B). 
     
     
         3 . The chair of  claim 2 , wherein said first retention recess ( 21 ′) and said second retention recess ( 21 ″) are made on opposite sides of said at least one first housing seat ( 20 ) and are substantially spaced by an angle equal to 180°. 
     
     
         4 . The chair of  claim 1 , wherein said locking pin ( 41 ) comprises a main body ( 413 ), substantially cylindrical, which is provided with a lateral surface;
 wherein said elastic retention element ( 411 ) is extended radially projecting from the lateral surface of said main body ( 413 );   wherein said support structure ( 2 ) is provided with an internal surface, which is directed towards said at least one first retention seat ( 20 ) and laterally delimits said at least one first retention seat ( 20 ); and   wherein said first retention access ( 21 ′) and said second retention recess ( 21 ″) are made in a depression from the internal surface of said support structure ( 2 ) along a radial extension direction.   
     
     
         5 . The chair of  claim 4 , wherein said elastic retention element ( 411 ) has a U shape, wherein said elastic retention element ( 411 ) is provided with:
 a convex portion ( 411 ′) that projects radially from the lateral surface of said main body ( 413 ) and is configured to be engaged in said first retention recess ( 21 ′) and second retention recess ( 21 ″), and   two connection arms ( 411 ″) which connect the convex portion ( 411 ′) to said main body ( 413 ), are configured for being bent during rotation of said locking pin ( 41 ) around said rotation axis (R), and allow elastic deformation of said elastic retention element ( 411 ).   
     
     
         6 . The chair of  claim 1 , wherein said support structure ( 2 ) is provided with at least one first stop shoulder ( 22 ), which is placed in at least one said first housing seat ( 20 ), and said locking pin ( 41 ) comprises at least one first stop element ( 412 ), which is susceptible of abutting against the at least one first stop shoulder ( 22 ) in order to prevent said locking pin ( 41 ) from rotating in a release sense, which is opposite said constraint sense. 
     
     
         7 . The chair of  claim 6 , wherein said locking pin ( 41 ) comprises main body ( 413 ), substantially cylindrical, which is provided with a lateral surface;
 wherein said first stop element ( 412 ) comprises an elastic tab, which is extended projecting from the lateral surface of said main body ( 413 ) up to a free end ( 412 ′);   wherein said elastic tab is configured for being bent between:
 am extended position, in which the free end ( 412 ′) of said elastic tab is placed spaced from the lateral surface of said main body ( 413 ) and said elastic tab is susceptible of abutting against said first stop shoulder ( 22 ) in order to prevent said locking pin ( 41 ) from rotating in said release direction; and 
 a bent position, in which the free end of said elastic tab is placed approached to the lateral surface of said main body ( 413 ) in order to allow free rotation of said locking pin ( 41 ) in said constraint sense. 
   
     
     
         8 . The chair of  claim 1 , wherein said support structure ( 2 ) is provided with at least one second stop shoulder ( 23 ), which is placed in said at least one first housing seat ( 20 ), and wherein said locking pin ( 41 ) comprises at least one second stop element ( 414 ), which is susceptible of abutting against the at least one second stop shoulder ( 23 ) in order to prevent said locking pin ( 41 ) from rotating in said constraint sense, when said locking pin ( 41 ) is in said constraint position (C). 
     
     
         9 . The chair of  claim 1 , wherein:
 said locking pin ( 41 ) has a substantially L shape, wherein said non-circular head ( 410 ) is extended substantially orthogonal to said rotation axis (R) and is provided with a first abutment wall ( 418 ), which is directed towards the at least one first opening ( 200 ) of said at least one first housing seat ( 20 );   said at least one support element ( 3 ) being provided with a second abutment wall ( 33 ), substantially planar, which is placed in said second housing seat ( 30 ) and against which the first abutment wall ( 418 ) of said non-circular head ( 410 ) is susceptible of abutting,   in order to constrain said locking pin ( 41 ) in said second housing seat ( 30 );   
       wherein the first abutment wall ( 418 ) of said non-circular head ( 410 ) has:
 at least one first section ( 418 ′), which is tilted with respect to the second abutment wall ( 33 ) of said at least one support element ( 3 ) by a first angle (α), and 
 a second section ( 418 ″), which is tilted with respect to the second abutment wall ( 33 ) of said at least one support element ( 3 ) by a second angle (β), which is greater than said first angle (α); 
 
       wherein, when said locking pin ( 410 ) is in rotation in said constraint sense, said second section ( 418 ″) is susceptible of intercepting the second abutment wall ( 33 ) of said at least one support element ( 3 ), previously with respect to said at least one first section ( 418 ″). 
     
     
         10 . A method of mounting the chair of  claim 1 , wherein the method comprises:
 a step of arranging said support structure ( 2 ) provided with said at least one first housing seat ( 20 ) provided with said non-circular first opening ( 200 );   a step of arranging said at least one support element ( 3 ), selected from among a back ( 31 ) and a pair of arms ( 32 ) and provided with said second housing seat ( 30 );   a step of inserting said locking pin ( 41 ) in the at least one first opening ( 200 ) of the at least one first housing seat ( 20 ) of said support structure ( 2 );   a locking step, in which said locking pin ( 41 ) is rotated around said rotation axis (R) in said constraint sense, up to said at least one release position (B), in order to retain said locking pin ( 41 ) in said at least one first housing seat ( 20 ) and mounted in said support structure ( 2 );   a step of connecting said at least one support element ( 3 ) to said support structure ( 2 ), with said second housing seat ( 30 ) aligned and communicating with said at least one first housing scat ( 20 );   a fixing step, in which said locking pin ( 41 ) is rotated around said rotation axis (R) in said constraint sense, up to said constraint position (C), in order to constrain said support structure ( 2 ) and said at least one support clement ( 3 ).