Seat Articulating Device

Abstract

The invention concerns a seat articulating device comprising a seat and a back capable of pivoting relative to the back seat about a pivot pin (A 1 ) into a plurality of positions, in particular a nominal position wherein the back is substantially vertical and a shelf position wherein the back is folded down on the seat, said device comprising: a flange ( 3 ) designed to support the back pivoting relative to the pivot pin (A 1 ) including arc-shaped teeth having a radius R centered on the pivot pin (A 1 ); a concave toothed segment ( 12 ) capable of being linked to the seat, oscillating relative to a pivot pin (A 2 ) between a locking position wherein it co-operates with the teeth of the flange ( 3 ) and an unlocking position wherein it is spaced apart from the flange teeth and allows the flange ( 3 ) to rotate. The invention is characterized in that it comprises: a projecting part ( 6 ) of the flange surface ( 3 ) forming an arc-shaped ramp ( 7 ) centered on the pivot pin (A 1 ) having a radius r smaller than the radius R of the teeth wherein is provided a groove ( 8 ), and an oscillating lever ( 23 ) located in the same plane as the projecting part ( 6 ) of the flange ( 3 ), coaxial and superimposed to the toothed segment ( 12 ) including a tooth ( 27 ) capable of sliding on the ramp ( 7 ), when the back pivots between the nominal position and the shelf position and capable of being locked in the groove ( 8 ) of the projecting part when the seat is in the shelf position.

1 . A device for articulating a seat comprising a seat cushion and a backrest that can pivot with respect to the seat cushion about first articulation axle into multiple positions, particularly a nominal position in which the backrest is more or less vertical and a table position in which the backrest is folded down onto the seat cushion, this device comprising: 
 a side plate intended to support the pivoting backrest with respect to the first articulation axle and having a toothset in the form of an arc of a circle centered on the articulation axle,    a concave toothed sector that can be connected to the seat cushion, pivoting with respect to second articulation axle between a locking position in which it collaborates with the toothset of the side plate and an unlocking position in which it is distant from the toothset of the side plate and allows the side plate to rotate,    a projecting part projecting from a surface of the side plate ( 3 ) and forming a ramp in the form of an arc of a circle centered on the first axle of rotation and of radius smaller than a radius of the toothset and exhibiting a cut-out, and    a pivoting lever lying in the same plane as the projecting part of the side plate, coaxial and superposed with the toothed sector and having a tooth able to slide along the ramp as the backrest is pivoted between the nominal position and the table position and able to click into the cut-outs of the projecting part when the seat is in the table position.    
   
   
       2 . The device as claimed in  claim 1 , wherein the projecting part has a stop surface which faces the tooth when the seat is in the nominal position.  
   
   
       3 . The device as claimed in  claim 1 , wherein the toothed sector has a boss which engages in a slot made in the lever.  
   
   
       4 . The device as claimed in  claim 1 , wherein the toothed sector has a bearing surface adjacent to a cut-out bounded by a snouts, the device additionally comprising a primary finger pivoting with respect to an axle between a locking position in which it is in contact with the bearing surface, keeping the toothed sector in mesh with the toothset of the side plate, and an unlocking position in which the primary finger faces the cut-out and comes to bear against the snout in order to cause the toothed sector to pivot.  
   
   
       5 . The device as claimed in  claim 4 , wherein a spring is positioned on the axle about which the primary finger pivots, the action of this spring tending to cause the primary finger to pivot against the bearing surface of the toothed sector.  
   
   
       6 . The device as claimed in one of  claim 4 , wherein the lever has a bearing surface adjacent to a cut-out, the device additionally comprising a secondary finger engaged on the same axle of pivoting as the primary finger, pivoting between a position in which it is in contact with the bearing surface so as to keep the lever in an angular position such that the tooth is engaged in the cut-out of the projecting part of the side plate and an angular position in which the tooth of the lever slides along the ramp as the backrest pivots about the first axle.  
   
   
       7 . The device as claimed in  claim 6 , wherein the primary finger and the secondary finger are oriented with respect to one another in such a way that, in the nominal position, the primary finger is in contact with the bearing surface of the toothed sector and the secondary finger is in contact with the bearing surface of the lever and in such a way that, in an intermediate position between the table position and the nominal position, the primary finger bears against the snout of the toothed sector and the secondary finger is engaged in the cut-out of the lever.  
   
   
       8 . The device as claimed in  claim 1 , wherein elements of the device are enclosed in a casing that is closed by a cover.  
   
   
       9 . The device as claimed in  claim 1 , further comprising a hairpin spring which bears against the toothed sector and against the lever.  
   
   
       10 . The device as claimed in  claim 8 , wherein the casing is equipped with a stop against which the side plate comes to bear on the backrest in the backward nominal position against which the side plate bottoms out, in the table position.