Seat back for a vehicle seat comprising an integrated protective device

Abstract

The invention concerns a seatback for a vehicle seat, having an integrated protective device. The protective device includes a device that generates a torque acting in a pivoting direction on an upper back part, a rear-end impact detector that is-in effective connection with the torque-generating device in such a way that the device is activated in the event of the rear-end impact and the pivoting motion is initiated, and an immobilization device for retention of the upper back part in the normal use position.

1 . A seatback for a vehicle seat, the seatback having an integrated protective device, comprising: 
 a lower back part adapted to be joined to a seat part;    an upper back part that is pivotable relative to the lower back part out of a normal use position, about an axis extending in the seatback transversely to a longitudinal vehicle axis, through an angular range in a pivoting direction pointing in a direction of vehicle travel, as a result of a torque acting in the pivoting direction, into a safety position;    a device for generating the torque;    means for detecting a rear-end impact; and    immobilization means for retention of the upper back part in the normal use position;    wherein the device for generating the torque comprises a force storage device or an energy storage device acting irrespective of any occupancy of the vehicle seat, the means for detecting a rear-end impact comprising a vehicle crash sensor and the immobilization means comprising a lever system, the vehicle crash sensor being in effective connection with the force storage device or the energy storage device, and with the lever system constituting the immobilization means for retention of the upper back part, such that in the event of the rear-end impact, the retention of the upper back part in the normal use position is nullified, the force storage device or the energy storage device is activated, and the upper back part is pivoted in the pivoting direction.    
   
   
       2 . The seatback of  claim 1 , wherein there is attached in or on the upper back part a headrest which in the event of a rear-end impact is moved out of a comfort position, in which a spacing between the headrest and a seat user's head is approximately 40 to 110 mm, into an interception position, in which the spacing between the headrest and the seat user's head is zero or almost zero.  
   
   
       3 . The seatback of  claim 1 , further comprising a second immobilization means for retention of the upper back part against a backward motion out of the safety position into the normal use position.  
   
   
       4 . The seatback of  claim 1 , wherein the lever system of the immobilization means for retention of the upper back part in the normal use position comprises an interlock lever joined immovably to the upper back part, and to the torque-generating device, the interlock lever pivotable about the pivot axis of the upper back part, and secured in a locked position by a locking bolt.  
   
   
       5 . The seatback of  claim 4 , wherein in the locked position, the locking bolt engages through an elongated opening of the interlock lever, out of which it is moved in order to release the torque-generating device.  
   
   
       6 . The seatback of  claim 4 , wherein the torque-generating device is a torsion spring and wherein the interlock lever is joined to the torsion spring via a recoil lock that blocks any pivoting of the upper back part in the direction out of its normal use position into its safety position, but permits it in the opposite direction.  
   
   
       7 . The seatback of  claim 6 , wherein the recoil lock is embodied as a self-locking rolling-element or wedge-type lock, operating positively or nonpositively, preferably by jamming, or as a ratchet device, in such a way that it makes possible immobilization even in positions located between the safety position and the normal use position of the upper back part.  
   
   
       8 . The seatback of  claim 3 , wherein the second immobilization means is respectively embodied as a self-locking rolling-element or wedge-type lock that operates positively and/or nonpositively, or as a ratchet device, the second immobilization means making possible immobilization against a backward motion even in positions located between the safety position and the normal use position of the upper back part.  
   
   
       9 . The seatback of  claim 3 , wherein the second immobilization means is configured as a rolling-element locking device comprising a ring gear, arranged concentrically about the pivot axis of the upper back part, that is arranged inside a cylindrical shell, as well as rolling elements arranged between the teeth of the ring gear and between the ring gear and the shell.  
   
   
       10 . The seatback of  claim 3 , wherein the second immobilization means is configured as a recoil lock that comprises a cylindrical inner part, arranged concentrically about the pivot axis of the upper back part, that is arranged within a shell part, as well as rolling elements or jamming wedges arranged in receptacles of the shell part.  
   
   
       11 . The seatback of  claim 3 , wherein the second immobilization means is configured as a recoil lock that comprises a cylindrical inner part having a smooth enveloping surface or one structured to increase friction or equipped with a coating, and an eccentrically mounted pivoting body engaging nonpositively on the enveloping surface of the inner part.  
   
   
       12 . The seatback of  claim 3 , wherein the second immobilization means is configured in such a way that the second immobilization means limits any recoil play of the upper back part to a maximum angular magnitude of one degree.  
   
   
       13 . The seatback of  claim 1 , wherein the means for detecting a rear-end impact are in effective connection with the immobilization means for retention of the upper back part in the normal use position, and the immobilization means are in effective connection with the torque-generating device, in such a way that in the event of the impact, a release of the torque-generating device is accomplished by the immobilization means by means of a pyrotechnic device.