Abstract:
Disclosed is a device for limiting the movement of rotatably mounted parts, especially pivotable upholstery elements of vehicle seats ( 1 ). Said device comprises a locking piece ( 7 ) which is disposed inside the rotatably mounted part and can be made to releasably engage with a thrust bearing ( 15 ). The inventive locking piece ( 7 ) effectively cooperates with a control device ( 10 ) that is located in the area of the joint ( 4 ) of the rotatably mounted part.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]     This application is the National Stage of International Application No. PCT/EP2003/011533, filed Oct. 17, 2003 and claims benefit to German Application No. 10249100.3, filed Oct. 21, 2002, both of which are incorporated herein by this reference. 
     
    
     FIELD  
       [0002]     The invention relates to a device for limiting the movement of rotatably mounted parts, in particular pivotable upholstery elements of vehicle seats, having a locking piece which is arranged inside the rotatably mounted part and which can be made to releasably engage with a counter-bearing, and to correspondingly equipped vehicle seats.  
       BACKGROUND  
       [0003]     A device of the generic type is disclosed by the published patent application DE 44 35 835 A1. The rear seat unit for a motor vehicle described therein is equipped with a vertically divided backrest, the backrest segments of which are rotatably mounted in the transition to the seat part and independently of one another can be folded forwards from an upright position of use into a horizontal transport position.  
         [0004]     Since cargo situated in the luggage space can strike the rear side of the upright backrest in the event of a frontal impact, and can expose this to considerable forces, in the event of an accident the backrest segments can be bolted together by means of a bolt horizontally displaceable transversely to the direction of travel. If cargo strikes one backrest segment, not only is the rotational movement of the latter limited by lateral locking on the body side, but the forces are also dissipated by way of said bolt to the body-side locking of the other backrest segment. This limiting of movement improves the safety of the vehicle occupants.  
         [0005]     The bolt is displaced by means of a spring energy accumulator or a pyrotechnic charge, which is activated by a deceleration sensor responding to a high rate of vehicle deceleration.  
         [0006]     Such systems are technically expensive and in addition harbor certain dangers for the vehicle occupants due to the high bolt speeds.  
         [0007]     Thus there is a need to provide a movement-limiting device which is reversible and which affords a conspicuously simple design construction.  
       SUMMARY OF THE INVENTION  
       [0008]     There is provided a locking piece that operatively interacts with a control device situated in the area of the joint of the rotatably mounted part of a vehicle seat.  
         [0009]     The operative interaction is preferably achieved by means for the mechanical transmission of force, in particular by a Bowden cable. It is also feasible, however, to use a connecting rod linkage or a hydraulic device for this purpose.  
         [0010]     The locking piece advantageously comprises a bolt, preferably arranged so that it is longitudinally displaceable in the rotatably mounted part, the bolt being extendable from one of the end faces of the part, for example, but being fully retracted into the part when not in use. This improves not only the visual appearance of the locking device but also the occupant safety.  
         [0011]     In order to bring the bolt automatically into engagement with the counter-bearing, the latter may have an inclined and/or arched end face. In this case the bolt, even in the operative position, can preferably be pushed into the part against the action of a spring, so that as it strikes the counter-bearing it recoils, but then engages in an undercut section of the counter-bearing.  
         [0012]     One embodiment of the device for limiting movement includes a control device that has a mechanical guide, in relation to which the rotatably mounted part is angularly adjustable. The mechanical guide may comprise a control cam, a guideway or an eccentric disc, for example.  
         [0013]     It is of particular advantage if the counter-bearing acts as limit stop in one direction of rotation of the rotatably mounted part, and as releasable catch device in the opposite direction of rotation. Thus, for example, an upholstery part of a vehicle seat can be pivoted right into a limit position, in which it is safeguarded against forcible overturning. Overturning might occur, for example, under the effect of loading in the event of an accident or it might be caused by misuse. On the other hand it can easily be pivoted back as soon as a predefined release force is exceeded.  
         [0014]     There is also provided a vehicle seat having at least one rotatably mounted upholstery element, the movement of which is limited by a device previously described. In such a vehicle seat, for example, the movement of a from a substantially upright position onto the seat part is limited. It is furthermore possible to use the limiting device in the context of a vehicle seat having a seat part that can be folded from a substantially horizontal position of use away from the backrest into a vertical or horizontal transport position. The device can equally well be designed so as to limit the movement between segments of the backrest that can be folded from substantially upright positions of use onto the seat part into horizontal transport positions. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The drawings represent various exemplary embodiments of a vehicle seat and a device for limiting movement of a rotably mounted part in schematic form.  
         [0016]      FIG. 1  shows a side view of a first vehicle seat equipped with an exemplary embodiment of a device for limiting movement in a position of use.  
         [0017]      FIG. 2  shows the vehicle seat according to  FIG. 1  in a transport position  
         [0018]      FIG. 3  shows an enlargement of the locking piece used in the vehicle seat according to  FIGS. 1 and 2  in an extended position  
         [0019]      FIG. 4  shows the locking piece according to  FIG. 3  in a retracted condition  
         [0020]      FIG. 5  shows a control device, suitable for use in the arrangement, in two operative positions  
         [0021]      FIG. 6  shows an exemplary embodiment of a vehicle seat equipped in a position of use including an exemplary embodiment of a device for limiting movement.  
         [0022]      FIG. 7  shows the vehicle seat according to  FIG. 6  in a transport position  
         [0023]      FIG. 8  shows a front view of an exemplary embodiment of a bench seat with divided backrest and a locking of the backrest segments including a device for limiting movement.  
         [0024]      FIG. 9  shows an enlarged section X-X from  FIG. 8   
         [0025]      FIG. 10  shows a control device for the bench seat according to  FIG. 8   
         [0026]      FIG. 11  shows another exemplary embodiment of a vehicle seat equipped including an exemplary embodiment of a device for limiting movement in a position of use  
         [0027]      FIG. 12  shows the vehicle seat according to  FIG. 11  in a transport position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     The vehicle seat  1  shown in  FIGS. 1 and 2  comprises a seat part  3  connected to the vehicle floor  2 , and a backrest  5  rotatably connected thereto in the area of a joint  4 . The backrest  5  can be folded from a substantially upright position of use ( FIG. 1 ) in the direction of another vehicle seat  6  arranged in front of this into a horizontal transport position ( FIG. 2 ).  
         [0029]     The vehicle seat  1  with a movement limiting device is provided in the area of the backrest  5  remote from the joint with a locking piece  7 , provided with a bolt  9  that can be pushed out of the upper end face  8  of the backrest  5 . A control device  10  comprising a control cam  11  and a feeler  12  is arranged in the area of the joint  4 . The feeler  12  and the bolt  9  operatively interact by way of a mechanical force-transmitting device  13  in the form of a Bowden cable  14  in such a way that the feeler  12 , which is pressed in by the control cam  11  when the backrest  5  is folded forwards, pushes the bolt  9 , connected to the other end of the Bowden cable  14 , forwards above the end face  8 .  
         [0030]     As can be seen from  FIG. 2 , the bolt  9  can now be releasably latched in a counter-bearing  15  situated on the rear of the other vehicle seat  6 . This serves, on the one hand, to present a predefined resistance to the return of the backrest  5 , and on the other to prevent any forcible overturning of the backrest  5  due to overloading of the rear side  16 .  
         [0031]     The locking piece  7  depicted in  FIGS. 3 and 4  comprises the bolt  9  which, when the backrest  5  is folded forwards (arrow A) into the transport position, is pushed out of the backrest  5  (arrow B) by the Bowden cable  14  assisted by a compression spring  17  and then protrudes from its end face  8 . The bolt  9  is naturally withdrawn against the resistance of the compression spring  17 . As it engages in the counter-bearing  15 , the bolt  9 , rounded with a domed shape at its projecting end, overcomes a first projection  19  integrally formed thereon, which is relatively short and which is passed over as the bolt  9  recoils when the backrest  5  is folded in the direction of the arrow A. The bolt  9  springing back into its projecting position then lies in a recess  20  on a further, more salient projection  21  of the counter-bearing  15 , which can no longer be overcome, even under high load, and which serves as limit stop for the rotational movement of the backrest  5 .  
         [0032]     During the brief compression the bolt  9 , due to a cavity  22  which is let into the latter and in which the end piece  23  of the Bowden cable  14  can move, can be displaced in relation thereto, so that there is no reaction on the control device  10 .  
         [0033]     When the backrest  5  is folded back into the position of use (arrow C), the bolt  9  is first disengaged from the recess  20  under renewed compression and is then retracted into the backrest  5  (arrow D) until its domed end is aligned approximately flush with the end face  8 . In this position it is largely invisible and does not adversely affect the handing of the vehicle seat  1 .  
         [0034]     The locking piece  7  is mechanically connected by way of the Bowden cable  14  to the control device  10  shown in  FIG. 5 , which comprises a control cam  11  fixed to the seat part and a feeler  12  pivoting with the backrest  5 . The feeler  12  has a pin  24 , which is pressed onto the contour of the control cam  11  by means of a compression spring  25 . The compression spring  25  must obviously have a greater stiffness than the compression spring  17  acting in the locking piece  7 , which is essentially intended to permit releasable engagement of the bolt  9  in the counter-bearing  15 . The pin  24  is pushed in as it runs over the contour of the control cam (forwards folding of the backrest  5 , arrow A), the bolt  9  being pushed out by the Bowden cable  14 , or forced back out by the compression spring  25  when the bolt  9  is retracted (rearwards folding of the backrest, arrow C).  
         [0035]     In the vehicle seat according to  FIGS. 6 and 7  both the backrest  5  and also the seat part  3  are folded from a position of use ( FIG. 6 ) into a transport position ( FIG. 7 ). For this purpose the seat part  3 , on its side remote from the backrest, is rotatably connected by means of a further joint  26  to the vehicle floor  2 , and can be pivoted from the horizontal position into a vertical position, in which it bears, for instance, on the other vehicle seat arranged in front of it. The backrest of the vehicle seat  1  can then be pivoted forwards into a horizontal position.  
         [0036]     In order to protect the front vehicle seat  6  from cargo striking it in the event of an accident, a protective plate  27  can be drawn out of the seat part pivoted into the vertical position. The forces acting thereon are dissipated via the joint  26  and a locking piece  7  arranged in the seat part, connected to a counter-bearing  15 , into the vehicle floor  2  and/or the front vehicle seat  6 . The locking piece  7  is arranged in the area of the seat part  3  facing the backrest and is provided with a bolt  9  which can be run out of the relevant end face  8  and which also engages in the counter-bearing  15  as soon as the seat part is situated in a vertical position.  
         [0037]     The locking piece  7  and counter-bearing  15  correspond in function and construction to the embodiment previously described.  
         [0038]     A vehicle bench seat  28  equipped with an exemplary embodiment of a movement limiting device and having a divided backrest  5  is depicted in  FIG. 8 . The backrest  5  is divided into backrest segments  29 . 1 ,  29 . 2 , which independently of one another can be pivoted forwards by means of joints  4 . 1  to  4 . 3  onto the seat part  3 .  
         [0039]     In order to dissipate overloads, which in the event of an accident act upon the rear side of a backrest segment  29 . 1 ,  29 . 2 , through the entire backrest  5 , the segments  29 . 1  and  29 . 2  in their upright position of use can be interconnected by way of two locking pieces  7 . 1 ,  7 . 2 , one of which is arranged in each backrest segment  29 . 1  and  29 . 2  and which engages in a counter-bearing  15 . 2 ,  15 . 1  in the other backrest segment  29 . 2 ,  29 . 1 . In a departure from the embodiments previously described, bolts  9 . 1 ,  9 . 2  of the locking pieces  7 . 1 ,  7 . 2  are in this case actuated so that they are run out in the position of use but are retracted when folding over into the transport position and do not impede a passenger sitting next to the folded backrest segment  29 .  
         [0040]     As can be seen from  FIG. 9 , at the occurrence of a force F acting on the backrest segment  29 . 1  this is supported by way of the longer projection  29 . 1  on the bolt  9 . 2  of the other backrest segment. Should the force act on the other backrest segment  29 . 2 , the force is transmitted by way of the laterally inverted locking piece  7 . 1 . Both backrest segments  29 . 1 ,  29 . 2  are in turn connected by way of lateral arresting mechanisms  30 . 1 ,  30 . 2  to the vehicle body. The movement limiting device therefore serves to distribute any force acting off-center to both of the arresting mechanisms  30 . 1  and  30 . 2 .  
         [0041]     The locking pieces  7 . 1 ,  7 . 2  are actuated by way of two control devices  10 . 1 ,  10 . 2  arranged in the area of the middle joint  4 . 2  and connected to Bowden cables  14 . 1  and  14 . 2 .  
         [0042]     In order to be able to fold the backrest segment  29 . 1  forward separately, the projection  21 . 1  designed to rotate in the counter bearing  15 . 1  must be temporarily pivoted backwards by means of an actuating device (not shown). The other backrest segment  29 . 2  is similarly released by an actuation of the counter-bearing  15 . 2 . The articulated support for the projections  21 . 1  and  21 . 2  must obviously be provided with a releasable locking which is capable of withstanding the loads in the event of an accident.  
         [0043]     As shown in  FIG. 10 , the control devices  10  are in principle of similar design construction to the embodiments previously represented. The control cams  11  are designed, however, so that the pin  24  is pushed in when the backrest  5  is in the upright position and the bolt  9  is consequently run out.  
         [0044]     The vehicle seat according to  FIGS. 11 and 12  largely corresponds to the embodiment according to  FIGS. 6 and 7 , but in contrast to this the seat part  3  in the joint  26  can be folded approximately 180° forwards into a horizontal transport position, thereby increasing the load floor considerably.