Patent Document

CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present application is a continuation of International Application PCT/EP2004/006403, which was filed Jun. 15, 2004. The entire disclosure of International Application PCT/EP2004/006403, which was filed Jun. 15, 2004, is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a bearing in a vehicle seat, in particular in an automobile seat, with the bearing having a bearing bolt and an element supported on the bearing bolt.  
         [0003]     DE 44 39 644 C2 discloses a locking device with a bearing of the type described in the immediately preceding paragraph, for locking a fitting in a vehicle seat with a swing-free backrest, with the locking device having a spring loaded loading element for loading a locking pawl, and a catch element for supporting the locking pawl in the event of a crash, the loading element and the catch element being made in one piece or in two pieces with a slot-and-bolt guide for coupling. In practice, improvements remain to be made, for example with respect to precision requirements in manufacturing.  
       BRIEF SUMMARY OF SOME ASPECTS OF THE INVENTION  
       [0004]     An aspect of the present invention is the provision of improvements to a bearing of the type mentioned above. In accordance with one aspect of the present invention, a bearing for a vehicle seat, in particular an automobile seat, has a bearing bolt and an element supported on the bearing bolt. The bearing bolt extends into a hole of the supported element. The hole and/or the bearing bolt have a cross-section that is different from a circle.  
         [0005]     By providing the hole, which bears on the bearing bolt, and/or the bearing bolt with a cross section that is different from a circle, one avoids the supported element being borne at a single point, which would cause undesirable rolling of the supported element on the bearing bolt. Depending on the impacting forces, such undesired rolling could result in there being a quick change of position. Higher precision in manufacturing, which would otherwise have to compensate for the consequences of the rolling, is thus made unnecessary. By choosing the appropriate cross-sectional shape of the hole and/or the bearing bolt (preferably an at least generally polygon shape, i.e. with straight and, if needed, curved sections, for example as an approximately quadrangular cross-section, in particular a square cross-section with substantially rounded corners) the supported element can bear on the bearing bolt in at least two touch points, thus maintaining a stable position, over a certain angle area, when there is change in the impacting forces. The hole and/or the bearing bolt can have almost any form between a monogon (which, apart from a rounded corner, has a circular shape) and a polygon including the shape of a star, with two straight sections being preferably at an angle of 90° with respect to one another. It is sufficient for only one of the partners (i.e., the hole and the bearing bolt) to have such a cross-section. The respective other partner may then have a circular cross-section.  
         [0006]     The bearing according to the invention is particularly useful in a locking device, namely for at least one locking element and/or at least one securing element. One of the touch points lies preferably approximately in the direction of the contact point between the supported element and a locking element and/or a control element connected to it, from where the largest forces are transferred in the event of a crash. Preferably, both securing elements are supported on a common bearing bolt, both having a hole according to the invention.  
         [0007]     The locking device with a bearing according to the invention, with the locking device comprising a corresponding securing device if needed, can be used for a variety of adjusters, i.e. both for rotational adjusters such as, for example, fittings in vehicle seats having a backrest with adjustable inclination and/or a swing-free backrest, and for linear adjusters such as, for example, longitudinal adjusters or height adjusters in diagonal struts. The locking device according to the invention can also be used for a lock for detachably attaching the vehicle seat to the vehicle structure or for locking a foldable vehicle seat into different positions. Depending on their purpose, the locking elements to be secured differ in their structure, whereas the securing elements can remain basically the same.  
         [0008]     Other aspects and advantages of the present invention will become apparent from the following.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     In the following, the present invention is explained in more detail with reference to an exemplary embodiment which is illustrated in the drawings, in which  
         [0010]      FIG. 1A  is a partial section through the exemplary embodiment in the area of the bearing of the securing element, in a normal position,  
         [0011]      FIG. 1B  is a partial section through the exemplary embodiment corresponding to  FIG. 1A , in the event of a crash,  
         [0012]      FIG. 2A  is a partial section in the area of the bearing of the previously known securing element corresponding to  FIG. 1A , in a normal position,  
         [0013]      FIG. 2B  is a partial section through the bearing of the previously known securing element corresponding to  FIG. 2A , in the event of a crash,  
         [0014]      FIG. 3  is a partially sectioned view of a fitting, and  
         [0015]      FIG. 4  is a schematic representation of a vehicle seat. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     A fitting  1  designed to serve as a detent fitting for a vehicle seat  3  is provided with a lower fitting part  5  that is fixed to structure of the seat part of the vehicle seat, and an upper fitting part  8  that is fixed to structure of the backrest of the vehicle seat. The lower fitting part  5  includes two basically flat plates that are assembled to define the construction space of the lower fitting part  5 . The upper fitting part  8  is at least partially arranged inside the construction space of the lower fitting part  5 . The upper fitting part  8  is rotatable around a backrest bolt  10  relative to the lower fitting part  5 . The vehicle seat  3  has two mirror-image lock fittings  1  bearing the inclination-adjustable and pivotable backrest of the vehicle seat  3 . A locking device  11  of the fitting  1  includes a gear wheel rim  12  and a locking pawl  15 . The gear wheel rim  12  is on the upper fitting part  8 . The gear wheel rim  12  is curved around the backrest bolt  10  in the area facing away from the backrest on the upper fitting part  8 . The locking pawl  15  is arranged inside the construction space of the lower fitting part  5 , and is pivotably supported on a pawl bearing bolt  13 . The locking pawl  15 , as a first locking element, and the gear wheel rim  12 , as a second locking element, cooperate by meshing depending on the relative position of the fitting parts  5  and  8 .  
         [0017]     A securing device  21  is provided for the locking device  11 . The securing device  21  has, as a first securing element, a generally flat loading eccentric  23  that is pivotably supported on a bearing bolt  25  of the lower fitting part  5  on that side of the locking pawl  15  that is facing away from the gear wheel rim  12 . When the fitting  1  is in a locked position, a pre-loaded spiral spring  27  presses the loading eccentric  23  against a control cam  29  that is rotationally fixed to the locking pawl  15 , so that the teeth of the locking pawl  15  are pressed into the gear wheel rim  12  (e.g., the locking pawl  15  and the control cam  29  can be collectively referred to as a locking element, which is for meshing with the gear wheel rim  12 ).  
         [0018]     In addition, the securing device  21  has, as a second securing element, a generally flat catch element  31  that is also pivotably supported on the bearing bolt  25 . When in a normal position, the catch element  31  is arranged at a distance from the locking pawl  15  that is small compared with the height of the teeth, and is pressed against a lower fitting part-fixed stop  35  that is fixed to the lower fitting part  5 . The catch element  31  is pressed against a lower fitting part-fixed stop  35  by means of a pre-loaded, helical-like closing spring  33  that is arranged in a receiving groove of the catch element  31  and acting between the loading eccentric  23  and the catch element  31 . In the event of a crash, a torsional moment acts on the upper fitting part  8 , having an opening effect of the locking pawl  15  and attempting to press the loading eccentric  23  shut. The locking pawl  15 , however, after a minimal pivoting movement, supports itself on the catch element  31  in such a way that meshing between the locking pawl  15  and the gear wheel rim  12  is maintained.  
         [0019]     The loading eccentric  23  and the catch element  31  are coupled by means of a slot-and-bolt guide. This slot-and-bolt guide consists of an unlocking bolt  37  on the catch element  31  and a slot  39  formed in the loading eccentric  23 . The slot  39  is curved around the bearing bolt  25 . When unlocking the fitting  1 , the catch element  31  is pivoted back against the spring loads via the unlocking bolt  37 , so that the closing spring  33  becomes compressed even further. If the spring force built up by this is larger than that of the spiral spring  27  or, at the latest once the unlocking bolt  37  reaches the end of the slot  39 , the loading eccentric  23  is pulled along, i.e. is opened against its spring load. As soon as the catch element  31  comes to bear against a radially protruding carry-along area of the locking pawl  15 , the catch element  31  carries along the locking pawl  15 , thereby opening the locking pawl  15  and unlocking the fitting  1 .  
         [0020]     For the loading eccentric  23  and the catch element  31  to pivot easily during operation in all tolerance positions, they are sitting on the bearing bolt  25  with little clearance. The consequences arising from this are now going to be explained in detail using the loading eccentric  23  for an example.  
         [0021]     The bearing bolt  25  is positioned in a hole  43  of the eccentric  23 , whereby the eccentric  21  sits on the bearing bolt. The hole  43  has a slightly larger cross-section than the bearing bolt  25 . The bearing bolt  25  has a circular cross-section. In normal conditions, the relation of forces is determined both by the closing force of the tangentially acting spiral spring  27  and the reaction force in the contact point K between the loading eccentric  23  and the control cam  29 . A resulting force F then acts in the area of the hole  43 , running at an oblique angle from the line connecting the contact point K and the center of the bearing bolt  25  and defining the point where the loading eccentric  23  bears against the bearing bolt  25 . In the event of a crash, major crash forces are transferred via the contact point K which greatly determine the relation of forces, so that a resulting force F is then acting in the area of the hole  43 , approximately running along the line connecting the contact point K and the center of the bearing bolt  25 .  
         [0022]     In a conventional securing element with a round bearing hole R, the location A of the securing element bearing against the bearing bolt  25  would also change due to the change in the resulting force F, by a sliding and rolling movement. Thereby the center of the securing element would be shifted by something close to 10% of the depth of the meshing.  
         [0023]     According to the present invention, the hole  43  does not have a circular cross-section but has four additional enlargements of the radius that can also be seen as strongly rounded corners of a square, there occurring no jumps in the gradient and the hole  43  therefore having a smooth rim around its convex cross-sections. Given the chosen shape of the holes  43 , the loading eccentric  23  bears against the bearing bolt  25  in two touch points B, “touching” meaning tangential contact. One of the touch points B seen from the bearing bolt  25  lies approximately in the direction of the contact point K with the control cam  29 , i.e. eventually in the direction of the locking pawl  15 . Thanks to this double support, there is no rolling movement or shifting of the center even in the event of a change in direction of the resulting force K (over a sector of approximately 90°), i.e. the loading eccentric  23  that continues to bear against the bearing bolt  25  in the two touch points B functions in a case-independent manner.  
         [0024]     The conditions are analogous when a force is applied to the backrest, for example by seizing and pressing on the upper edge of the backrest. In this case, the direction of the force F changes as well, but the loading eccentric  23  continues to bear on the bearing bolt  25  in the two touch points B, so that the play of the backrest is almost reduced to zero.  
         [0025]     For the catch element  31 , which has a corresponding hole, the same conditions apply as for the loading eccentric  23 .  
         [0026]     It will be understood by those skilled in the art that while the present invention has been discussed above with reference to exemplary embodiments, various additions, modifications and changes can be made thereto without departing from the spirit and scope of the invention as set forth in the following claims.

Technology Category: 7