Locking device for office chairs and the like

Abstract

Locking device ( 1 ) for office chairs and the like comprising of a first locking element ( 9 ) operatively associable to a base unit ( 3 ) of a chair and a second locking element ( 10 ) operatively associable at least to a revolving portion ( 6 ) of the chair. The first and second locking elements ( 10 ) are selectively associable in an active position to lock the rotation of the revolving portion ( 6 ) in respect to a base unit ( 3 ) and detachable in a passive position to unlock such rotation. The shifting between the active position and the passive position takes place along a shifting direction ( 11 ) substantially perpendicular to the contrasting force developing between the locking elements ( 9, 10 ) in active position. The shifting direction ( 11 ) is also substantially perpendicular to the components of the contrasting force, tangential and perpendicular to the contact surfaces between the engaging portions ( 9 a , 10 a ).

1 . Locking device ( 1 ) for office chairs and the like comprising: 
 a first locking element ( 9 ) having a first engaging portion ( 9   a ) and operatively associable to a base unit ( 3 ) of a chair;    a second locking element ( 10 ) having a second engaging portion ( 10   a ) and operatively associable at least to a revolving portion ( 6 ) of the chair, pivoted on the said base unit ( 3 ) of the chair, said first engaging portion ( 9   a ) and said second engaging portion ( 10   a ) being selectively associable in an active position to lock the rotation of the revolving portion ( 6 ) in respect to the base unit ( 3 ) and dissociable in a passive position to unlock such rotation, said first and second engaging portions ( 9   a ,  10   a ) being reciprocally faced in said active position to exchange a contrasting force between each other, the shifting between said active position and said passive position taking place along a shifting direction ( 11 ) substantially perpendicular to said contrasting force, characterized in that at least one of said first and second locking elements ( 9 ,  10 ) is mobile in said shifting direction ( 11 ) in a parallel way to the surface of its own engaging portion ( 9   a ,  10   a ).    
   
   
       2 . Device according to  claim 1  characterized in that said shifting direction ( 11 ) is substantially perpendicular also to the components, of said contrasting force, tangential and perpendicular to the contact surfaces between the engaging portions  9   a ,  10   a.    
   
   
       3 . Device according to  claim 1  characterized in that the shifting between said active position and said passive position takes place through a relative lateral displacement of said first and second engaging portions ( 9   a ,  10   a ).  
   
   
       4 . Device according to  claim 1 , characterized in that first and second engaging portions ( 9   a ,  10   a ) are reciprocally faced in said active position in correspondence of a contact surface, said shifting direction ( 11 ) being substantially parallel to said contact surface.  
   
   
       5 . Device according to  claim 1 , characterized in that said shifting direction ( 11 ) is substantially parallel to the rotating axis ( 13 ) of the revolving portion ( 6 ).  
   
   
       6 . Device according to  claim 1 , characterized in that said second locking element ( 10 ) is fixed to said revolving portion ( 6 ) and said first locking element ( 9 ) is assembled in a translational way on said base unit ( 3 ).  
   
   
       7 . Device according to  claim 1 , characterized in that said second engaging portion ( 10   a ) is provided with a number of resting seats, said first engaging portion ( 9   a ) being selectively associable with said engaging seats.  
   
   
       8 . Device according to  claim 1 , characterized in that said second locking element ( 10 ) is a wheel at least partially toothed.  
   
   
       9 . Device according to  claim 1 , characterized in that said first locking element ( 9 ) is provided with a number of teeth cooperating with said second engaging portion ( 10   a ).  
   
   
       10 . Device according to  claim 9 , characterized in that said teeth are all cooperating contemporarily with said second engaging portion ( 10   a ) in said active operative position.  
   
   
       11 . Device according to  claim 1 , characterized in that said first locking element ( 9 ) is constituted by a portion of a circular crown completely toothed and cooperating with said second engaging portion ( 10   a ).  
   
   
       12 . Device according to  claim 1 , characterized in that it includes two of said first locking ( 9 ,  9 ′) and two of said second locking elements ( 10 ,  10 ′) respectively cooperating to lock the rotation of said revolving portion and suitably placed on opposite sides of the revolving portion ( 6 ) to avoid the unbalancing of the revolving portion ( 6 ) in locking position.  
   
   
       13 . Device according to  claim 1 , characterized in that it includes also operating means ( 14 ) operatively connected to said first locking element ( 9 ) to operate the locking and the unlocking of the device ( 1 ).  
   
   
       14 . Device according to claim, characterized in that said operating means ( 14 ) are common to the said two first locking elements ( 9 ,  9 ′).  
   
   
       15 . Device according to  claim 13 , characterized in that said operating means ( 14 ) include a push rod ( 15 ) assembled in a revolving way on said base unit ( 3 ) and driven manually, on which is assembled in a translational way said first locking element ( 9 ).  
   
   
       16 . Device according to  claim 15 , characterized in that said operating means ( 14 ) include also cam shaped means ( 16 ) operatively associated to said push rod ( 15 ) to convert the rotary movement of the push rod ( 15 ) in a translational movement of the first locking element ( 9 ) along the rod ( 15 ).  
   
   
       17 . Device according to  claim 16 , characterized in that said cam means ( 16 ) include a small pivot ( 17 ) integral with and transversal to said rod ( 15 ) and an operating element ( 18 ) associated in a moving way to said rod ( 15 ) and provided with a cam track ( 19 ) in which is inserted the said small pivot ( 17 ).  
   
   
       18 . Device according to  claim 17 , characterized in that said cam track ( 19 ) is provided with a central transferring portion ( 19   a ) and of two end portions ( 19   b ,  19   c ), corresponding to said active and passive positions, said end portions ( 19   b ,  19   c ) having substantially a perpendicular development to said shifting direction ( 11 ) to impede the accidental shifting of the command element ( 18 ) when the locking is in active and passive position.  
   
   
       19 . Device according to  claim 17 , characterized in that it includes also an elastic element ( 20 ) operatively connecting said first locking element ( 9 ) and said second operating element ( 18 ), to provide for the functions of pre-selection and anti-shock of the locking.  
   
   
       20 . Device according to  claim 1 , characterized in that it includes also a containing element ( 21 ) to hold said first locking element ( 9 ) in the various operative positions.  
   
   
       21 . Device according to  claim 1 , characterized in that said first and second locking elements ( 10 ) are provided with a corresponding set of gear teeth having an involute profile.  
   
   
       22 . Device according to  claim 1 , characterized in that the said first and second locking element ( 10 ) are provided with a corresponding set of gear teeth having an undercut profile.  
   
   
       23 . Device according to  claim 1 , characterized in that said first engaging portion ( 9   a ) and said second engaging portion ( 10   a ) are parallel to the shifting direction ( 11 ).  
   
   
       24 . Device according to  claim 23 , characterized in that said first engaging portion ( 9   a ) and said second engaging portion ( 10   a ) are provided with resting seats and with corresponding resting teeth developing perpendicularly to the shifting direction ( 11 ).  
   
   
       25 . Device according to  claim 1 , characterized in that said first engaging portion ( 9   a ) and said second engaging portion ( 10   a ) are perpendicular to the shifting direction ( 11 ).  
   
   
       26 . Device according to  claim 25 , characterized in that said first engaging portion ( 9   a ) and said second engaging portion ( 10   a ) are provided with resting seats and with corresponding resting elements developing parallel to the shifting direction ( 11 ).  
   
   
       27 . Mechanism ( 2 ) for office chairs and the like, comprising of: 
 a base unit ( 3 ) fit to engage, through a connecting element ( 4 ), at the top end of an upright ( 5 ) which defines the vertical support of the chair, a supporting element ( 7 ) of a back of the chair engaged in a revolving way to said base unit ( 3 ), a supporting element ( 8 ) of a seat of a chair mounted above said base unit ( 3 ), means of elastic support placed at least between said supporting element ( 7 ) and said base unit ( 3 ),    characterized in that it includes a locking device ( 1 ) according to  claim 1 , to lock selectively the swinging of at least said supporting element ( 7 ) of the back in respect to said base unit ( 3 ).    
   
   
       28 . Mechanism according to  claim 27 , characterized in that said supporting element ( 8 ) of the seat is swively associated to the base unit ( 3 ) to swing in respect to the base unit ( 3 ) in an independent way from said supporting element ( 7 ) of the back and by the fact to include also a second locking device ( 1 ), according to  claim 1 , operatively placed in between said supporting element ( 8 ) of the seat and said base unit ( 3 ), said means of elastic support being provided also between said supporting element ( 8 ) of the seat and said base unit ( 3 ).  
   
   
       29 . Chair characterized in that it includes a locking device ( 1 ) according to  claim 1 .  
   
   
       30 . Chair characterized in that it includes a mechanism ( 2 ) according to  claim 27.