Abstract:
Inclination adjustment fitting for back rest of a vehicle seat includes first fitting part affixed to seat section, and second fitting part affixed to back rest, and which fitting parts are relatively pivotable around a pivoting axis. The two fitting parts include gearings forming components of a wobble gearing and roll on one another under influence of eccentric elements rotated around the pivoting axis. Eccentric element includes an eccentric ring, on which two wedge segments covering regions of eccentric ring lie in a mirror-image arrangement, and which are forced away from one another in the sense of an increase in eccentricity by a spring. Under excessive load, force transfer between fitting parts not accomplished via wedge segments; rather, a contact cam forming a single piece with eccentric ring projects into gap between end surfaces of wedge segments, transfers load via a contact surface from second fitting part first fitting part.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority of German Application No. 10 2005 026 658.4, filed Jun. 9, 2005, and which is incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to an inclination adjustment fitting for the back rest of a vehicle seat that includes a first fitting part affixed to seat section, and second fitting part affixed to back rest, and which fitting parts are relatively pivotable around a pivoting axis.  
       BACKGROUND OF THE INVENTION  
       [0003]     Inclination adjustment fittings of this type are provided with internal or external gearing, which are produced by stamping using metal sheet cutouts of the fitting parts. In this, the external gearing has at least one less tooth than the number of teeth in the internal gearing, and one of the fitting parts bears against eccentric elements which are rotatable around the pivoting axis, and which in turn bear against the other fitting part. The eccentric elements used in inclination adjustment fittings of the type under discussion are comprised of two wedge segments, which bear directly or indirectly against the one fitting part, and which are forced apart in a peripheral direction in the sense of an increase in eccentricity by means of a stored-energy device, generally a spring. In this manner, any play in the gearing and in the mounting is eliminated. With actuation of the eccentric elements around the pivoting axis of the inclination adjustment fitting, the internal gearing of the one fitting part rolls on the external gearing of the other fitting part, which causes the fitting part that is affixed to the back rest to pivot relative to the fitting part that is affixed to the seat in a manner corresponding to the difference in the number of teeth.  
         [0004]     In DE 10 2004 013 272 B3 an inclination adjustment fitting of this type is described. In this fitting, the wedge segments transfer the load from the fitting part that is affixed to the back rest to the fitting part that is affixed to the seat. This can lead to problems, particularly in the case of an excessive load.  
         [0005]     The same problems can occur with the inclination adjustment fitting of this type that is disclosed in DE 103 28 300 A1. With this inclination adjustment fitting, the eccentric ring is provided with a contact cam, which is designed to form a single piece with the eccentric ring, and which projects into the gap between the end surfaces of the wedge segments. The purpose of this contact cam is to limit the shifting of the wedge segments, in order to prevent an overload of the spring that acts upon the wedge segments.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0006]     An object of the present invention is to provide an inclination adjustment fitting of this type, in which at least in the event of an excessive load, the transmission of force from fitting part to fitting part does not occur via the wedge segments.  
         [0007]     This object is achieved according to the invention with an inclination adjustment fitting for the back rest of a vehicle seat that includes a first fitting part affixable to a vehicle seat, a second fitting part affixable to a back rest of a vehicle seat, and the first fitting part being pivotable relative to the second fitting part around a pivoting axis. A wobble gearing is provided that includes gearings, and the fitting parts, and the gearings rolling on one another under influence of an eccentric element. The eccentric element is rotatable around the pivoting axis, and is provided with an eccentric ring, on which two wedge segments which cover regions of the eccentric ring lie, and the two wedge segments are arranged in a mirror image. The wedge segments are forced away from one another in a sense of an increase in eccentricity by spring elements resting against their end surfaces at one end, and the end surfaces having a gap between them created by their lateral spacing from one another. Carrier elements are arranged between the other end surfaces of the wedge segments for the purpose of impinging upon the wedge segments and against the force of the spring device. The eccentric elements bear the first fitting part affixable to a seat section of a vehicle seat, and the second fitting part affixable to the back rest bearing the eccentric elements. A contact cam is provided that is configured to form a unitary piece with the eccentric ring, projecting into a gap formed between the end surfaces of the wedge segments. The contact cam including a contact surface configured to transfer a load via the contact surface from the second fitting part affixed to the back rest, in use, to the first fitting part affixed to the seat section of a vehicle seat, in use.  
         [0008]     According to the invention, the contact cam, which is configured to form a single piece with the eccentric ring and which projects into the gap that exists between the end surfaces of the wedge segments, has a contact surface that serves to transfer the load from the fitting part that is affixed to the back rest to the fitting part that is affixed to the seat.  
         [0009]     In one advantageous embodiment of the invention, the contact surface of the contact cam is arranged at a slight radial distance from the fitting part that is affixed to the back rest. This radial spacing is configured such that under normal operating conditions the wedge segments ensure the absence of play in the fitting while serving to produce the degree of eccentricity required to adjust the fitting, and such that in the event of an excessive load the contact surface is placed in contact with the fitting part that is affixed to the back rest as a result of the deformation of fitting components, so that loads are transferred from the back rest, via the contact cam of the eccentric ring, to the seat, and from there to the body of a vehicle.  
         [0010]     In another advantageous embodiment of the invention, the contact surface of the contact cam is in continuous contact with the fitting part that is affixed to the back rest. Thus a so-called fixed eccentric is created, and the wedge segments serve only to compensate for any play that may be present due to geometric and positional tolerances. In this case it is advantageous for the contact surface to be configured as large as possible, in order to reduce the specific surface load.  
         [0011]     When in the above description a contact between the contact cam and the fitting part that is affixed to the back rest is described, this, of course, refers not only to direct contact but also to indirect contact, for example contact via a bearing ring positioned between the two.  
         [0012]     Relative terms such as up, down, left, and right are for convenience only and are not intended to be limiting.  
         [0013]     Below, the invention will be described in greater detail with reference to one exemplary embodiment. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  shows the components of an inclination adjustment fitting of the invention, in an exploded, perspective representation;  
         [0015]      FIG. 2  shows an illustration according to  FIG. 1  from a different viewing angle;  
         [0016]      FIG. 3  shows a side view of the assembled inclination adjustment fitting;  
         [0017]      FIG. 4  shows a perspective view of the representation shown in  FIG. 3 , in the direction opposite the arrow A, with the end cap removed;  
         [0018]      FIG. 5  shows a view of the embodiment of  FIG. 3  in the direction of the arrow A;  
         [0019]      FIG. 6  shows a cross-section B-B of  FIG. 5 ; and  
         [0020]      FIG. 7  shows a cross-section C-C of  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     An inclination adjustment fitting  1  depicted in the set of drawings is a component of an unillustrated vehicle seat, which comprises a seat component and a back rest, and by which the inclination of the back rest component relative to the seat component can be adjusted by means of the inclination adjustment fitting  1 . To this end, the inclination adjustment fitting  1  comprises a fitting part  2  affixed to the seat component or section and a further fitting part  3  affixed to the back rest. Both fitting parts  2 ,  3  are deep-drawn steel sheet blanks, by which the fitting part  2  is provided with an external gearing  4  stamped out of the blank, and the fitting part  3  is provided with an internal gearing  5  stamped out of the blank. The external gearing  4  has the same modular configuration as the internal gearing  5 , but contains at least one less tooth. When the inclination adjustment fitting  1  is assembled, the external gearing  4  and the internal gearing  5  mesh with one another. The fitting part  3  is further provided with a rim hole  6  that has a circular through opening  7 . An inner bearing ring  8  can be slipped onto the rim hole  6 . The fitting part  2  is also provided with a circular through opening  9 , arranged concentrically relative to the external gearing  4 , into which an outer bearing ring  10  can be inserted.  
         [0022]     The bearing rings  8  and  10  serve as bearings for an eccentric element  11 . This includes an eccentric ring  12  and two identical wedge segments  13  that are arranged on said ring in a mirror-image position. When the fitting is assembled, the eccentric ring  12  is pushed onto the inner bearing ring  8 , the inner surfaces of the wedge segments  13  rest on an outer surface  12 . 1  of the eccentric ring  12 , and outer surfaces  13 . 2  of the wedge segments  13  rest against an inner surface  10 . 1  of the outer bearing ring  10 . This arrangement can be most clearly seen in the representation according to  FIG. 7 . In order to avoid the presence of only one contact point between the inner bearing ring  8  and an inner surface  12 . 2  of the eccentric ring  12 , which would result in a “wobbling” of the fitting part  3  on the fitting part  2 , the inner surface  12 . 2  of the eccentric ring  12  is out-of-round relative to the inner bearing ring  8 , so that at least two contact points are provided between these two components. Inner surfaces  13 . 1  of the wedge segments  13  also do not rest flat against the outer surfaces  12 . 1  of the eccentric ring  12 . The mutual curvatures of the inner surfaces  13 . 1  and the outer surfaces  12 . 1  are configured such that linear contact is created between them. The outer surfaces  13 . 2  of the wedge segments  13 , in contrast, have the same curvature as the inner surface  10 . 1  of the outer bearing ring  10 . The wedge segments  13  thus lie flat against the outer bearing ring  10 .  
         [0023]     The outer surface  12 . 1  of the eccentric ring  12 , which is covered by the wedge segments  13 , tapers upwardly forming a wedge shape relative to its inner surface  12 . 2 . The wall thickness of the eccentric ring  12 , which is thereby increased, is used at the end of the upward taper to form a projection  30  having a stop surface  30 . 1  that is oriented radially outward, by which this projection  30  is formed by a material offset to a smaller external dimension of the eccentric ring  12 . Stop surfaces  31 . 1  are allocated to these stop surfaces  30 . 1  of the eccentric ring  12 , positioned on a projection  31  that is oriented radially inward in the area of the narrow end surface  13 . 4  of the wedge segments  13 . Between the stop surfaces  30 . 1  and  31 . 1 , a gap exists when the eccentric elements  11  are not actuated. As a result of the upward tapering of the outer surface  12 . 1  of the eccentric ring  12 , the inner surfaces  13 . 1  of the wedge segments  13  are in contact with an opposing wedge surface. This opposing wedge configuration allows an optimal layout for the wedge angle of the wedge segments  13 .  
         [0024]     Symmetrically to the two projections  30  on the eccentric ring  12 , a stop cam  32  with two radial stop surfaces  32 . 1  is formed on the area of the eccentric ring  12  that is free from the wedge segments  13 , by way of an increase in the wall thickness of the eccentric ring  12 .  
         [0025]     By virtue of this insertion of the eccentric element  11  between the two fitting parts  2  and  3 , an eccentricity e is created between the central axis of the through opening  7  of the fitting part  3 , which forms the pivoting axis  14  of the inclination adjustment fitting, and the central axis  16  of the through opening  9  in the fitting part  2  (see  FIG. 3  and  6 ). This eccentricity e ensures that the external gearing  4  is forced into the internal gearing  5  of the fitting part  3  in an extension of the direction of the eccentricity e. In order to form this engagement of the external gearing  4  and the internal gearing  5 , along with the bearing of the two fitting parts  2  and  3 , without any play, the wedge segments  13  are acted upon by spring-loaded elements, such that they are forced away from one another peripherally on the eccentric ring  12  in the sense of an increase in eccentricity e. In the present exemplary embodiment an omega spring  15  is provided as the spring-loaded element, whose legs  15 . 1 , which are bent at right angles, bear against the end surfaces  13 . 3  of the wedge segments  13  that face one another, forcing the segments apart, as described.  
         [0026]     The above-described arrangement ensures that the inclination adjustment fitting  1  is held in place, free from play, in each adjusted position of inclination of the back rest, because the forces exerted by the back rest are radially absorbed by the wedge segments  13 ; in that manner, no adjustment forces are exerted on them. The tension exerted by the omega spring  15  on the wedge segments  13  can be relieved only by tangential forces acting on the wedge segments  13 . In order to introduce this type of adjusting motion on the eccentric elements  11 , a two-piece carrier comprised of a carrier hub  17  and a carrier disk  18  is provided. The carrier is described in greater detail below.  
         [0027]     Both the carrier hub  17  and the carrier disk  18  are made of metal. In this, the carrier hub  17  is configured as a die-cast piece, or forged component, and the carrier disk  18  is provided as a metal sheet punched component. The carrier hub  17  comprises a cylindrical center section  17 . 1 , a collar  17 . 2 , the diameter of which projects beyond the cylindrical center section  17 . 1 , and a thrust collar  17 . 3 , which is somewhat narrower in diameter and has an out-of-round cross-section, in other words its cross-section is configured to transmit torque. When the fitting is assembled, the center section  17 . 1  extends through the through opening  7  in the rim hole  6  with a small amount of radial play, with its collar  17 . 2  bearing against the fitting part  3  from the outside. On the other side of the inclination adjustment fitting  1 , the carrier disk  18  is pushed onto the thrust collar  17 . 3  of the carrier hub  17 . For this purpose, the carrier disk  18  is provided with a central opening  18 . 1  that has the same out-of-round cross-section as the thrust collar  17 . 3 . Once the carrier disk  18  has been pushed onto the thrust collar  17 . 3 , the carrier disk  18  rests non-rotatably on the carrier hub  17 . In order to axially affix the carrier disk  18  to the carrier hub  17 , the material of the thrust collar  17 . 3  is displaced onto the carrier disk  18 , creating lugs  19  that project outward relative to the cross-section of the central opening  18 . 1  of the carrier disk  18 , as is shown in  FIG. 6 . The carrier hub  17  and the carrier disk  18  are thus riveted to one another by means of the lugs  19 .  
         [0028]     As is also illustrated in  FIG. 6 , the collar  17 . 2  of the carrier hub  17 , which bears against the fitting part  3 , and the carrier disk  18 , which bears against the fitting part  2  on the opposite side of the adjustment fitting  1 , create an axial clamping of the two fitting parts  2  and  3 , supplementary to the retainers, which are not shown in the drawings. These holding plates or retainers are welded to the fitting parts  2  and  3  via weld projections  20 , and each overlaps the respective opposite fitting part  2  or  3  in areas along the periphery of the internal gearing  5  or the external gearing  4 .  
         [0029]     The carrier disk  18  is provided with two expressed carrier fingers  21 . When the inclination adjustment fitting  1  is assembled, each of these carrier fingers  21  engages in a gap that forms between the eccentric ring  12  and the outer bearing ring  10 . In this manner, when the eccentric elements  11  are not actuated, the end surfaces  21 . 1  of the carrier fingers lie a peripheral distance from the end surfaces  13 . 4  of the wedge segments  13  that face away from the omega spring  15 . This peripheral distance between the end surfaces  21 . 1  and  13 . 4  is provided in order to prevent the restriction of the adjustment movement of the wedge segments  13  by the omega spring  15  that would be caused by the premature contact of these two surfaces  13 . 4  and  21 . 1 . In this situation the other end surfaces  21 . 2  of the carrier fingers  21  are also spaced from the stop surfaces  32 . 1  of the stop cam  32 .  
         [0030]     In addition to the carrier fingers  21 , the carrier disk  18  is also provided with openings  22  and  23 . The legs  15 . 1  of the omega spring  15  extend through the opening  22 , while the openings  23  are used in the attachment of a plastic end cap  24  on the carrier disk  18 . To accomplish this, catch nubs  25  are provided on the end cap  24 , which can be inserted into the openings  23  and latched at the backs of the openings. As a supplementary latching element, a spring tab  26  is provided on the end cap  24 , which engages in the opening  22  in the carrier disk  18  and latches behind it.  
         [0031]     The end cap  24  serves to cover the omega spring  15  and the carrier disk  18 , and especially to cover the open articulation area of the inclination adjustment fitting  1 , in order to protect this area from contamination, especially during painting operations.  
         [0032]     The end cap  24  is provided with a hub formed by two tabs  27 , which can be positively inserted into a central recess  28  in the carrier hub  17 . In this arrangement, the inner surfaces of the tabs  27  rest against an out-of-round cross-section  29  for the positive accommodation of a drive shaft that is not illustrated here (see  FIG. 5 ). This drive shaft is used to introduce a quantity of torque to the inclination adjustment fitting  1  and can be a part of a hand-operated wheel or a motor-driven shaft. At the ends of the tabs  27  on the end cap  24 , latching tabs  27 . 1  that project radially outward are provided. Once the tabs  27  have been inserted into the carrier hub  17 , these latching tabs latch behind a shoulder in the recess  28 , as is shown in  FIG. 6 . When the drive shaft is installed, the tabs  27  can no longer be compressed radially inward, which serves to ensure the engagement between the tabs  27 . 1  and the shoulder.  
         [0033]     The configuration of the end cap  24  that is described here, in conjunction with the carrier hub  17 , ensures a secure axial fastening to the inclination adjustment fitting  1  and a supplementary axial clamping of the two fitting parts  2  and  3 . Furthermore, the plastic tabs  27  arranged between the drive shaft and the carrier hub  17  prevent a metal-metal contact between the drive shaft and the carrier hub  17 , whereby undesirable rattling sounds are prevented.  
         [0034]     For details on the functioning of the inclination adjustment fitting  1 , attention is directed to the relevant description in the above-cited patent application DE 10 2004 013 272 B3, which is incorporated herein by reference.  
         [0035]     The inclination adjustment fitting  1  described in the present exemplary embodiment differs from that of the patent application DE 10 2004 013 272 B3 in that in this case a contact cam  34 , which is configured to form a single piece with the eccentric ring  12  and is provided with a contact surface  34 . 1 , projects into the gap  33  which is formed between the end surfaces  13 . 3  of the wedge segments  13 . This contact surface  34 . 1  is positioned a slight radial distance from the inner surface  10 . 1  of the bearing ring  10 . This distance is configured such that under normal operating conditions the wedge segments  13  both ensure the absence of play in the inclination adjustment fitting  1 , and provide the eccentricity e that is required for the shifting of the inclination adjustment fitting  1  once the inclination adjustment fitting has been released. In the case of an excessive load, the distance between the contact surface  34 . 1  and the inner surface  10 . 1  of the bearing ring  10  is overcome by means of the deformation of the bearing rings  8  and  10  and of the rim hole  6 , in other words the contact surface  34 . 1  of the contact cam  34  comes into contact with the inner surface  10 . 1  of the bearing ring  10 . In this manner, the load is transferred from the back rest via the contact cam  34 , bypassing the wedge segments  13 , into the fitting part  2  and from there via the seat section into the body of a vehicle.  
         [0036]     In a further unillustrated embodiment of the present invention, the contact surface  34 . 1  of the contact cam  34  is continuously in contact, in other words even during normal operation, with the inner surface  10 . 1  of the bearing ring  10 . In this manner a fixed eccentric is created, that is, the function of the wedge segments  13  in producing a degree of eccentricity which is necessary for the shifting of the inclination adjustment fitting  1  is eliminated. They serve only to compensate for a degree of play that may be present due to geometric and positional tolerances. In this case, the contact surface  34 . 1  is to be configured as large as possible, in order to reduce the specific surface load. It goes without saying that with this embodiment as well, an excessive load is reliably diverted via the contact cams  34  into the fitting part  2 .