Abstract:
A vehicle seat, in particular rear seat or rear bench, including a seat part, a backrest pivotally articulated to the seat part, whose position is variable between an upright seating or use position and a loading position folded forwards in direction of the seat part, a locking device arresting the backrest in the seating position, an unlocking device for unlocking the locking device for folding the backrest forwards from the seating position into the loading position, and an electromotive driving device for erecting the backrest from the loading position into the seating position. The unlocking device includes a manually actuatable release element and an electrically activatable unlocking means, so that electromotive erection or a fast manual erection of the backrest of a vehicle seat from the loading position into the upright seating is possible.

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
     This application is a National Phase Patent Application of International Patent Application Number PCT/EP2014/057340, filed on Apr. 11, 2014, which claims priority of German Patent Application Number 10 2013 206 688.0, filed on Apr. 15, 2013. 
     BACKGROUND 
     This invention relates to a vehicle seat, in particular a rear seat or a rear bench. 
     From EP 1 764 260 A1 a vehicle seat with a seat cushion and a backrest rotatably articulated to the rear end of the seat cushion is known, which backrest is variable between an upright condition and a condition folded forwards, in which it is inclined and folded towards the seat cushion or put over the seat cushion. A pretensioning means formed as spring exerts a force on the backrest in direction of the condition folded forwards, wherein a retaining mechanism arrests the backrest in the upright condition. An actuating element releases the retaining mechanism upon actuation, so that by action of the force of the pretensioning means the backrest is transferred into the condition folded forwards. 
     For rotating the backrest about its articulation at the rear end of the seat cushion, an electric motor activatable by means of a driver circuit is provided, with which the backrest can be guided back from the condition folded forwards into the upright condition. 
     Since folding up the backrest from the condition folded forwards into the predetermined, upright condition can be performed exclusively by means of the electric motor, the time period for folding up the backrest into the upright condition substantially depends on the power of the electric motor. For cost and space reasons small, high-speed electric motors usually are employed, which are connected with the backrest via a corresponding reduction gear for applying the required actuating force, so that folding up the backrest takes a frequently not accepted time period. 
     To carry out the tilt adjustment and folding down in an easy and convenient way in the case of an electromotive adjustment of a backrest, it is known from DE 102 09 759 A1 to vary the adjustment speed of the electromotive drive such that the inclination and adjustment function of the backrest is carried out with a slower speed than the folding function, so that at a slow speed the backrest inclination can be adjusted accurately, whereas the higher speed effects a fast execution of the folding function. 
     SUMMARY 
     It is an object underlying the present invention to selectively comfortably or quickly erect the backrest of a vehicle seat from a loading position folded forwards into an upright seating or use position. 
     The solution according to the invention selectively provides for a comfortable electric and/or electromotive or a fast manual erection of the backrest of a vehicle seat from a loading position folded forwards into an upright seating or use position. 
     The solution according to the invention thus provides for a comfort function in which the erection of the backrest from the loading position into the seating or use position is carried out by an electromotive driving device. For this purpose, it merely is required to actuate a control element integrated for example into the dashboard of a motor vehicle. Since the electromotive erection of the backrest however is effected comparatively slowly, a fast manual erection of the backrest from the loading position into the seating or use position is provided in the alternative, without acting on the electromotive driving device. 
     Both during the manual and during the electromotive erection of the backrest from the loading position into the seating or use position a pretensioning means can be tensioned and the backrest can be locked in the upright seating or use position, so that for folding the backrest forwards from the upright loading position into the seating or use position folded forwards the locking of the backrest is eliminated by actuating an unlocking means and the backrest is folded forwards. Alternatively, a pretensioning means can be omitted and the backrest can manually be folded down into the loading position. 
     The inventive solution to provide both a manual and an electromotive erection of the backrest becomes possible by decoupling the electromotive drive from the movement kinematics of the seat structure. 
     By decoupling the electromotive actuation of the erection of the backrest from a manual actuation on erection of the backrest it thus is possible to choose between the comfort function with electromotive actuation of the erection of the backrest and independent thereof the manual actuation for the fast erection of the backrest. 
     The electrically activatable unlocking means can be actuated either separate from the electromotive driving device for erecting the backrest from the loading position into the seating position for example by means of a relay, magnetic switch or the like or in a preferred embodiment by means of the electromotive driving device for erecting the backrest. 
     When using the electromotive driving device both for unlocking the backrest and for erecting the backrest from the loading position into the seating or use position, the electrically activatable unlocking means according to a preferred embodiment is actuated in the one direction of rotation of the driving device, whereas in the other direction of rotation of the electromotive driving device the backrest is erected from the loading position into the seating position. 
     Preferably, the unlocking device includes an unlocking lever rotatable about a lever axis with a control arm actuatable by means of the driving device and an unlocking arm releasing the locking device. Alternatively, the unlocking lever can be provided with a switching arm for manually unlocking the locking device, so that no additional actuating element is required for manually erecting the backrest from the loading position into the seating or use position by unlocking the locking device. 
     In a preferred embodiment, the unlocking arm rests against a locking pin of the locking device, which is guided in a locking link of the locking device, such that upon actuation of the unlocking device the locking pin is transferred from a locking position into an unlocking position for clearing the locking device. 
     After unlocking the locking pin, the unlocking arm is moved back into the starting position, while the locking pin remains in the unlocking position until the backrest is guided back into the seating position and is locked. 
     By unlocking the backrest locked in the seating position by means of the unlocking arm unilaterally resting against the unlocking pin and the independently effected return of the unlocking pin into the starting position by means of the lock locking the backrest in the seating position, the manual and the electromotive actuation of the backrest are decoupled from each other, so that both types of actuation are possible without the occurrence of functional overlaps. 
     The electromotive driving device contains an electric motor, a drive pinion connected with the electric motor, and a tooth segment meshing with the drive pinion, articulated to the seat part and pivotable about a tooth segment axis, from whose surface a control cam actuating the unlocking lever and an entraining element for erecting the backrest from the loading position into the seating or use position protrude, wherein the backrest is articulated to a backrest axle and is connected with a lifting device for erecting the backrest from the loading position into the seating or use position via a connecting tab articulation arranged at a distance from the backrest axle in folding direction of the backrest. 
     The lifting device consists of a lifting tab articulated to the seat part, which is engaged by the entraining element of the tooth segment for erecting the backrest from the loading position into the seating position, and a connecting tab which on the one hand is connected with the backrest via the connecting tab articulation and on the other hand is articulated to the lifting tab via a lifting bolt. 
     For pretensioning the upright backrest in direction of the loading position a pretensioning means can be provided, which preferably consists of a backrest spring acting between the seat part and the backrest. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in detail below with reference to an exemplary embodiment illustrated in the Figures of the drawing, in which further advantages and features of the invention are described in detail. The Figures of the drawing represent various phases of folding down and erecting the backrest of a vehicle seat. 
         FIG. 1  shows a side view of the functional elements for the electromotive or manual erection of a backrest in its upright seating or use position. 
         FIG. 2  shows a side view of the functional elements when manually or electrically unlocking the locking device for enabling folding down of the backrest from the upright seating or use position into the loading position. 
         FIG. 3  shows a side view of the functional elements during folding down of the backrest after unlocking of the locking device. 
         FIG. 4  shows a side view of the functional elements during the electromotive or manual erection of the backrest from the loading position into the seating or use position. 
         FIG. 5  shows a side view of the functional elements with the backrest electromotively or manually guided back into the starting position of the seating or use position, before locking the backrest in the seating or use position. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a side view of a seat part  1  of a vehicle seat, in particular of a rear seat or a rear bench, comprising a seat pan  21  articulated to the seat part  1  via a seat part axle  20  and a backrest  2  articulated to the seat part  1 , which can be folded forwards about a backrest axle  12  in direction of the arrow A plotted at the backrest  2  from an upright seating or use position as shown in  FIG. 1  into a loading position as shown in  FIG. 4 . In the loading position the backrest  2  rests on the seat cushion of the seat part  1  and is aligned horizontally to increase a storage space of the motor vehicle. 
     In the seating or use position of the backrest  2  as shown in  FIG. 1 , in which a vehicle occupant can sit down on the vehicle seat, the backrest  2  is pretensioned in direction of the arrow A, i.e. in forward folding direction, by means of a pretensioning means in direction of the loading position. The pretensioning means preferably consists of a non-illustrated backrest spring, which supports both on the seat part  1  and on the backrest  2 . 
     Folding the backrest  2  forwards from the upright seating or use position into the loading position folded forwards by action of the backrest spring is prevented by a locking device in the form of a latch  60  of a lock  6  shown in broken lines, which in the upright seating or use position blocks a lifting device  7  which is connected both with the seat part  1  and with the backrest  2 . The lifting device  7  consists of a lifting tab  8  which is articulated to the seat part  1  via a lifting tab articulation  14 , a connecting tab  9  which is articulated to the backrest  2  via a connecting tab articulation  13 , and a lifting bolt  10  which connects the lifting tab  8  with the connecting tab  9 . The lifting bolt  10  is trapped and blocked or released by the latch  60  and on actuation of the locking device moves along an oblong hole  11  in the seat part  1 . 
     The latch  60  of the lock  6 , which is pivotable about a lock axle  61  articulated to the seat part  1 , protrudes into the oblong hole  11  and blocks the lifting bolt  10  in direction of the arrow C plotted at the lifting bolt  10 , so that the backrest  2  pretensioned in forward folding direction is locked in the upright seating or use position as shown in  FIG. 1 . 
     For locking and unlocking the lock  6  a control device is provided in the form of a locking pin  62  guided in a locking link  63  according to  FIG. 2 , rotatable about the lock axle  61  and operatively connected with the latch  60 . For actuating the locking pin  62  an unlocking device is provided in the form of an unlocking lever  5  which is articulated to the seat part  1  via a lever axle  50  and includes a control arm  51  shown in  FIG. 1  in broken lines, an unlocking arm  52  branching off from the control arm  51 , which is shown in  FIG. 2  and is shown hatched for better visibility, and a switching arm  55 . In the starting position shown in  FIG. 1 , the unlocking arm  52  rests against the bottom side of the locking pin  62  of the lock  6  and can move the same in direction of the opposite end of the locking link  63  for unlocking the backrest  2  locked in the seating position. 
     An electromotive driving device includes a non-illustrated electric motor whose motor shaft is connected with a drive pinion  3 . The pinion teeth  30  of the drive pinion  3  mesh with the segment teeth  40  of a tooth segment  4  which is pivotable about a tooth segment axle  41  articulated to the seat part  1 . The tooth segment  4  includes a control cam  42  protruding from its surface and a bolt-shaped entraining element  43 , the function of which will be explained in detail below with reference to  FIGS. 2 to 5 . 
     Folding the backrest  2  down from the upright seating or use position shown in  FIG. 1  into the loading position shown in  FIG. 4  possibly by action of a pretensioning means pretensioning the backrest  2  in direction of the arrow A according to  FIG. 1  as well as the electromotively or manually actuated erection of the backrest  2  from the loading position shown in  FIG. 4  via an intermediate position shown in  FIG. 5  into the upright seating or use position shown in  FIG. 1  will now be described below. 
     For folding the backrest  2  forwards from the seating or use position into the loading position the electromotive driving device will be initiated after actuation of a switching element proceeding from the upright seating or use position of the backrest  2  as shown in  FIG. 1 , so that the drive pinion  3  connected with the non-illustrated electric motor is rotated in anti-clockwise direction and the tooth segment  4  meshing with the pinion teeth  30  with its segment teeth  40  is pivoted in clockwise direction about the tooth segment axle  41 . The control cam  42  of the tooth segment  4  thereby rests against the control arm  51  of the unlocking lever  5 , so that the same rotates about the lever axle  50  in anti-clockwise direction and thereby likewise lifts the hatched unlocking arm  52  in anti-clockwise direction. The locking pin  62  of the lock  6  resting against the unlocking arm  52  thereby is moved into the upper end position within the locking link  63  as shown in  FIG. 2 , which is opposite to the end position of the locking pin  62  as shown in  FIG. 1 , in which the latch  60  blocks the lifting bolt  10 . 
     By shifting the locking pin  62  into the upper end position, the latch  60  is pivoted about the lock axle  61 , so that the lifting bolt  10  is released. In the unlocking position shown in  FIG. 2 , the lifting bolt  10  thus can move freely within the oblong hole  11 , so that the backrest  2  for example can pivot about the backrest axle  12  by action of the pretensioning means and is folded forwards from the upright seating or use position into the loading position. 
       FIG. 3  shows the beginning of folding the backrest  2  forwards after unlocking the lock  6  by means of the electromotive driving device and the unlocking lever  5  acting on the locking pin  62  and hence on the latch  60 . The lifting bolt  10  is in an intermediate position  10 ′ within the oblong hole  11 , and the backrest  2  is slightly folded forwards with respect to the locked seating or use position according to  FIG. 1 . 
     After unlocking the lock  6 , the direction of rotation of the electric motor of the electromotive driving device is reversed, so that the drive pinion  3  is rotated in clockwise direction and the tooth segment  4  meshing with the pinion teeth  30  with its segment teeth  40  thereby is swiveled in anti-clockwise direction back into its starting position according to  FIG. 1  and entrains the unlocking lever  5  and hence the unlocking arm  52  into the starting position according to  FIG. 1 . Because of the unilateral abutment of the unlocking arm  52  against the locking pin  62 , the locking pin  62  remains in the upper end position within the locking link  63  and the lock  6  remains opened. Only after setting the backrest  3  back into the locked seating position and the related closing of a latch of the lock  6  is the locking pin  62  connected with the lock  6  again set back into its starting position according to  FIG. 1 . 
       FIG. 4  shows the backrest  2  in the loading position folded forwards or in a position shortly before reaching the loading position folded forwards, in which the lever guide  10 ″ has arrived in the region of the end of the oblong hole  11  opposite to the locking position. In this position, the backrest  2  rests on the seat cushion of the vehicle seat. 
     By again actuating the switching element for initiating the electromotive driving device the electric motor rotates the drive pinion  3  in clockwise direction, so that the tooth segment  4  meshing with the pinion teeth  30  with its segment teeth  40  is pivoted in anti-clockwise direction about the tooth segment axle  41 , until the entraining element  43  connected with the tooth segment  4  rests against the flank of the lifting tab  8  and pivots the same in anti-clockwise direction about the lifting tab articulation  14 . The lifting bolt  10  thereby is moved to the opposite end of the oblong hole  11  and with the same the connecting tab  9  is pivoted, which via the connecting tab articulation  13  erects the backrest  2  in direction of the arrow B according to  FIG. 4 . 
     During the erection of the backrest  2  as shown in  FIG. 5  the lifting bolt  10  moves against the latch  60 , which in the end position and seating or use position as shown in  FIG. 1  snaps shut and again locks the lifting bolt  10  and hence arrests the backrest  2  in the seating or use position. The locking pin  62  thereby is again moved back into its starting position according to  FIG. 1 . 
     The locking pin  62  thus is moved by means of the same driving device for unlocking the backrest  2 , which in the case of an electromotive actuation moves the backrest  2  from the loading position into the seating position. Independent thereof, the locking pin  62  however is again moved back into its starting position by the latch  60  snapping shut, when the backrest  2  is again erected into the seating position. 
     Folding the backrest  2  forwards also can be initiated without actuation of the electromotive driving device by means of a gearshift lever or pull handle arranged in the region of the driver seat or in the trunk, which for example via a connecting link such as a Bowden is connected with the switching arm  55  of the unlocking lever  5  and unlocks the lock  6 . An actuation of the switching arm  55  also can be provided exclusively for folding the backrest  2  forwards during assembly and removal of the vehicle seat by an assembler or for emergency actuation. 
     After opening of the lock  6 , folding the backrest  2  forwards proceeds as described above by manually folding the backrest  2  down from the seating or use position into the loading position or by action of a backrest spring tensioned during the preceding erection of the backrest  2  from the loading position into the seating or use position. 
     For manually erecting the backrest  2 , the backrest  2  is erected from the folded loading position, in which the backrest  2  rests on the seat cushion of the vehicle seat with the lock  6  opened, by simple manual actuation in direction of the arrow B according to  FIG. 4 , wherein during the upward movement the lifting bolt  10  moves against the latch  60  of the lock  6 , which in the end position with fully erected backrest  2  according to  FIG. 1  snaps shut and arrests the lifting bolt  10 . The backrest  2  thereby is blocked in the upright seating or use position and can again be folded forwards from the upright seating or use position into the loading position by unlocking the lock  6  manually or by action of the backrest spring.