Abstract:
A height-adjustable, belt-deflecting device for a seat belt including a deflecting element which deflects the seat belt. The device improves the safety of a vehicle occupant to be secured and protected by the seat belt. This is achieved by the having a deflecting element connected to a tightening device with which the seat belt can be tightened.

Description:
BACKGROUND 
   The invention relates to a height-adjustable, belt-deflecting device for a seat belt, in particular for a motor vehicle, having a belt-deflecting element which deflects the belt. Height-adjustable belt-deflecting devices of this type are also referred to as “height adjusters” for a seat belt and are conventionally fastened to the side body of the vehicle level with the shoulder of the vehicle occupant who is to be protected by the seat belt. 
   SUMMARY 
   The belt height adjustment device described herein addresses a need for a height-adjustable, belt-deflecting device for a seat belt, by means of which the safety of a vehicle occupant to be protected by the seat belt is improved. 
   Provision is made for the deflecting element to be connected to a tightening device with which the seat belt can be tightened. 
   One advantage of the height-adjustable, belt-deflecting device can be found in the fact that, owing to the tightening device, the seat belt can be tightened before and/or during an accident, as a result of which the seat belt is placed tightly against the vehicle occupant and positioned there; this pre-tightening ensures that the seat belt can fully deploy its protective function. 
   Another advantage of the height-adjustable, belt-deflecting device resides in the fact that the tightening device can be of relatively simple construction and can be very light in weight; this is because it acts merely on the deflecting element of the seat belt, which element is relatively light in weight and has little mass to be accelerated. The tightening device can, therefore, be dimensioned to be significantly smaller and lighter in weight than would be required, for example, if the tightening device had to act on a comparatively heavy belt retractor of the seat belt for the purpose of tightening the belt. 
   Provision is made for the tightening device to be composed so that it pulls or pushes the deflecting element essentially vertically upwards to tighten the seat belt. For example, three-point seat belts conventionally have a deflecting element level with the shoulder/chest region of the vehicle occupant, which element can be used to tighten the seat belt. Accordingly, it is proposed to arrange the tightening device on a deflecting element of this type, which is arranged at shoulder height, and to pull or push the latter vertically upwards for the purpose of tightening the seat belt. 
   The seat belt can be tightened particularly rapidly and strongly if the tightening device has a tightening spring which acts on the deflecting element to tighten the seat belt. It is therefore regarded as advantageous if the tightening device has a tightening spring of this type. The tightening speed and the tightening strength can be predetermined by appropriate dimensioning of the spring force of the tightening spring. With a tightening spring, a more rapid and stronger tightening of the seat belt can, in particular, be achieved than would be possible, for example, with a motor drive acting on the seat belt; at the very least, the motor would have to be of very large and powerful dimensions to achieve a comparable tightening speed and tightening strength. 
   The tightening spring may be a helical spring, as the tightening of the seat belt can be brought about in a simple and cost-effective manner with a helical spring. 
   To achieve a reversible operation of the tightening device, it is regarded as advantageous if the tightening device has a driving motor with which the tightening spring can be placed under a predetermined prestress. The provision of a driving motor configured for the tightening spring makes it possible to ensure that, after the prestressed tightening spring has been released for the first time, it can be reset back into its original, tightened state. In contrast with a pyrotechnic drive, for example, which can only be released a single time, a reversible or repeated operation of the tightening device can, therefore, be ensured with a tightening spring and associated driving motor. 
   The driving motor may be an electric motor, as an electric motor can be activated in a very simple manner. 
   The prestressing of the seat belt can be achieved in a structurally very simple manner if the deflecting element is connected to a rack in which a driving toothed wheel of the driving motor engages to prestress the tightening spring. 
   For the driving toothed wheel to be connected only to the rack when the tightening spring is to be tightened, it is regarded as advantageous if the driving toothed wheel is fastened on a driving shaft which can be displaced along its driving-shaft axis. With such an arrangement of the driving toothed wheel on a displaceable driving shaft, it can namely be achieved that, after the tightening spring has been stressed, the driving motor can be separated from the rack and the tightening spring, so that the tightening spring can be released without a reaction on the driving motor occurring or the latter being rotated at the same time. 
   In terms of structure, the electric motor may be arranged laterally next to the rack so that, by a lateral displacement of the driving shaft along the driving-shaft axis, the driving toothed wheel can be brought into engagement with the rack and conversely can be brought out of engagement with it. 
   In the case of such a lateral arrangement of the electric motor, the driving shaft may be essentially perpendicular with respect to the longitudinal axis of the rack. 
   To make it possible for the tightening process of the tightening spring to be activated electrically, it is regarded as advantageous if the lateral displacement of the driving shaft can be activated electrically. Such a displacement of the driving shaft can be achieved in a simple and, therefore, advantageous manner if there is an electric displacement device for the lateral displacement of the driving shaft. 
   To make it possible for the driving motor to be dimensioned to be as small as possible and for it to consume as little current as possible to tighten the tightening spring, it is regarded as advantageous if a gear is arranged between the driving shaft and the driving motor. A gear of this type preferably has a gear reduction of at least 1:100. 
   After the end of the tightening process and after separation of the electric motor from the tightening spring, to ensure that the tightening spring remains in its prestressed state, the tightening spring may be locked in its prestressed state by a locking device within the tightening device. 
   The locking device can be activated electrically to trigger the tightening process electrically. In particular, the locking device may, therefore, be able to be unlocked electrically. 
   Instead of a helical spring or a mechanical spring, the tightening spring may, for example, also be a compressed-air spring. To prestress a compressed-air spring of this type, a pump device, with which the compressed-air spring can be placed under pressure to prestress it, may be provided. 
   Instead of a pump device for filling the compressed-air spring, a compressed-air cartridge may also be provided as the compressed-air reservoir, the stored compressed air of which cartridge may be used to fill the compressed-air spring. 
   It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
       FIG. 1  shows an exemplary embodiment for a height-adjustable, belt-deflecting device according to an embodiment of the invention; and 
       FIGS. 2A-2D  show the manner in which the height-adjustable, belt-deflecting device of  FIG. 1  is used to tighten the seat belt and, after such a tightening process, to reset it back into its original state. 
       FIG. 3  shows another embodiment of the height-adjustable, belt deflecting device. 
   

   DESCRIPTION 
   Presently preferred embodiments of the invention are illustrated in the drawings. An effort has been made to use the same, or like, reference numbers throughout the drawings to refer to the same or like parts. 
   In  FIG. 1 , a three-point seat belt  1  which is connected at its one end  11  to a belt retractor  2  can be seen. The other end  12  of the seat belt  1  is fastened to a belt end fitting  3 . 
   The seat belt  1  runs from the belt retractor  2  via a deflecting element  41 , a deflector  20 , a deflecting buckle  5  and a further deflecting element  6  to the belt end fitting  3 . The deflecting buckle  5  can be locked releasably in a belt latch mechanism  7  via a buckle latch  51 . 
   The deflecting element  41  and the deflector  20  are parts of a height-adjustable, belt-deflecting device which is identified in  FIG. 1  by the reference number  4 . A double arrow  8  indicates that the deflecting element  41  of the height-adjustable, belt-deflecting device  4  can be moved vertically upwards and downwards. The seat belt  1  can therefore be tightened by moving the deflecting element  41 . The vertical deflection or movement of the deflecting element  41  takes place indirectly or directly by means of an electric motor  47 , the manner of operation of which is explained in detail in conjunction with  FIGS. 2A-2D . The deflector  20  can be adjusted manually and serves to set the height of the belt-deflecting device  4 . 
   The belt retractor  2 , the belt end fitting  3 , the further deflecting element  6  and the height-adjustable, belt-deflecting device  4  are attached to the side structure of the vehicle body; if the seat belt  1  is a three-point belt for an occupant who is situated in the front region of the vehicle, then the height-adjustable, belt-deflecting device  4 , the belt retractor  2 , the belt end fitting  3  and the further deflecting element  6  can be fastened in the region of the B-pillar  9  of the motor vehicle. 
   In the case of the exemplary embodiment of  FIG. 1 , only the upper deflecting element  41 , which is arranged level with the shoulder or chest region of the vehicle occupant, is part of a height-adjustable, belt-deflecting device  4 . Instead or else in addition, the further (lower) deflecting element  6  could also be provided with a corresponding, height-adjustable belt-deflecting device, so that the lap region  13  of the seat belt  1  could be tightened by a vertical displacement of the further (lower) deflecting element  6 . 
   The manner of operation of the height-adjustable, belt-deflecting device  4  is illustrated in detail in  FIGS. 2A-2D . 
   The deflecting element  41  which is fastened to a support  42  via lateral guide elements  410  can be seen in  FIG. 2A ; the deflecting element  41  is fastened to the support  42  so that the deflecting element  41  can be guided vertically upwards or downwards along the arrow direction  43 . 
   The deflecting element  41  is connected rigidly to a rack  44  which extends into the support  42 . A tightening spring  45 , which is compressed and is, therefore, prestressed in the illustration of  FIG. 2A , is fitted on the rack  44 . The tightening spring may, for example, be a helical spring. Owing to this prestress, the tightening spring  45  exerts a vertically upwardly directed force on the rack  44  and the deflecting element  41 . 
   In addition, a locking device  46  having a latching element  460  can be seen in  FIG. 2A . The latching element  460  has a latching lug which engages laterally in the serrated profile of the rack  44 . Owing to this engagement of the latching element  460 , the rack  44  and the deflecting clement  41  are fixed in the position illustrated in  FIG. 2A . 
     FIG. 2B  illustrates the manner in which the seat belt  1  of  FIG. 1  can be stressed by the belt-deflecting device  4 . Thus, an arrow  46   a  indicates the manner in which, by rotation of the latching element  460 , the latching lug of the latching element  460  is brought out of engagement with the rack  44 . In this position of the latching element  460 , the spring force of the tightening spring  45  can act directly on the rack  44  and the deflecting element  41  and can push the deflecting element  41  vertically upwards along the arrow direction  46   b.    
     FIG. 2C  shows the tightened position which is brought about by the tightening spring  45  and in which the deflecting element  41  has reached its upper maximum position. In this position, the seat belt  1  is tightened so that the seat belt  1  bears firmly against the vehicle occupant, in particular in the shoulder/chest region. 
   If there should not be an accident or not a severe accident after such a tightening of the seat belt  1 , then the deflecting element  41  is brought back into the activatable position of  FIG. 2A . An electric motor  47  is used for this. The electric motor  47  has a driving toothed wheel  470  which can be brought into engagement with the rack  44 . For this purpose, a driving shaft  471  connecting the driving toothed wheel  470  and the electric motor  47  is displaced laterally along its driving-shaft axis until the driving toothed wheel  470  comes into engagement with the rack  44 . The displacement of the driving shaft  471  is indicated by an arrow  472  in  FIG. 2D . 
   After the driving toothed wheel  470  has been brought into engagement with the rack  44 , the corresponding activation of the electric motor  47  causes the rack  44  to be pulled downwards, which is indicated by the reference number  473  in  FIG. 2D . The rack  44  is pulled downwards counter to the spring force of the tightening spring  45 , so that the tightening spring  45  is placed under compressive stress when the rack  44  is lowered. 
   As can be gathered in addition from  FIG. 2D , the latching lug of the latching element  460  is always in contact with the rack  44  as the deflecting element  41  is being pulled downwards; the latching element  460  is, therefore, configured so that it does not block a downwards movement along the arrow direction  473  of the rack  44  or deflecting element  41  and does not deploy an interfering action. 
   Only in the reverse direction, i.e., along the arrow direction of the arrow  46   b  of  FIG. 2B , does the latching lug of the latching element  460  block the rack  44 , so that the rack  44  remains in its position after the electric motor  47  is switched off. Even after the driving toothed wheel  470  has been pushed away counter to the arrow direction  472 , i.e., in the direction of the electric motor  47  the rack  44  remains in the position blocked by the latching element  460 . The tightening spring  45  cannot, therefore, push the rack  44  and therefore the deflecting element  41  upwards on account of the latching position of the latching lug of the latching element  460 . 
   After the driving toothed wheel  470  has been pushed back again in the direction of the electric motor  47 , the belt-deflecting device  4  is situated in the starting position which has already been explained in conjunction with  FIG. 2A . 
     FIG. 3  shows another embodiment of the height-adjustable, belt deflecting device. Instead of a helical spring or a mechanical spring, the tightening spring may, for example, be a compressed-air spring  245 . A pump device  246  may be provided with which the compressed-air spring  245  can be placed under pressure. 
   In summary, it can be established that the height-adjustable, belt-deflecting device  4  is completely reversible, as, after a first deflection of the deflecting element  41  upwards in the vertical direction, the said deflecting element  41  can be reset into the original initial position by the electric motor  47 . 
   The priority application, Germany Patent Application 103 09 696.5, filed Feb. 26, 2003 is incorporated by reference herein in its entirety. 
   Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is to be defined as set forth in the following claims.