Patent Publication Number: US-2009218843-A1

Title: Longitudinal adjustment apparatus for a vehicle seat

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims foreign priority benefits under 35 U.S.C. §119(a)-(d) to DE 10 2008 011 759.5, filed Feb. 28, 2008 and DE 10 2008 034 788.4, filed Jul. 25, 2008, which are hereby incorporated by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a longitudinal adjustment apparatus for a vehicle seat, and to a seat assembly including such an apparatus. 
     2. Background Art 
     A vehicle seat assembly may include a seat supported on a longitudinal adjustment apparatus that enables the seat to be positioned in multiple longitudinal positions. U.S. Pat. No. 6,126,133 discloses an example of such an apparatus. 
     SUMMARY OF THE INVENTION 
     In one embodiment, a longitudinal seat adjustment apparatus for a vehicle seat includes a first support member that is attachable to a vehicle, and a second support member that is moveable with respect to the first support member and configured to support the seat such that the seat is movable with the second support member. One of the support members has first and second lock portions that face each other, and the other support member has a third lock portion that is configured to be located between the first and second lock portions. The apparatus further includes a locking member that is movable generally vertically with respect to the support members between a locked position and an unlocked position for locking and unlocking the second support member with respect to the first support member. When the locking member is in the locked position, the locking member extends into the first, second and third lock portions. 
     While exemplary embodiments in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exemplary vehicle seat assembly including a seat back pivotally attached to a seat bottom, and a longitudinal seat adjustment apparatus that supports the seat bottom and seat back; 
         FIG. 2  is a top perspective view of a portion of the seat adjustment apparatus; 
         FIG. 3   a  is a side cross-sectional view of a portion of the seat adjustment apparatus showing upper and lower rails, a locking device for locking the upper rail with respect to the lower rail, and a release mechanism for unlocking the locking device; 
         FIG. 3   b  is a side cross-sectional view similar to  FIG. 3   a  showing the locking device in an unlocked position; 
         FIG. 4  is a side view of another exemplary embodiment of a locking device; 
         FIG. 5  is a perspective view of the seat adjustment apparatus, with the rails partially broken away to show the release mechanism; 
         FIG. 6  is a perspective cross-sectional view of the seat adjustment apparatus; 
         FIG. 7  is a cross-sectional end view of the rails; 
         FIG. 8  is a plan cross-sectional view of the seat adjustment apparatus showing a locking member of the locking device; 
         FIG. 9  is a cross-sectional view taken along line  9 - 9  in  FIG. 8  and viewed in the direction of the arrows; 
         FIG. 10  is a cross-sectional view taken along line  10 - 10  in  FIG. 8  and viewed in the direction of the arrows; 
         FIG. 11  is a cross-sectional view taken along line  11 - 11  in  FIG. 8  and viewed in the direction of the arrows; 
         FIG. 12  is a plan view of another exemplary locking member; 
         FIG. 13  is a side cross-sectional view of a portion of another exemplary lower rail for use with the locking member of  FIG. 12 ; 
         FIG. 14  is a side cross-sectional view of a portion of another exemplary upper rail for use with the locking member of  FIG. 12 ; and 
         FIG. 15  is a side cross-sectional view of portions of the locking member and rails assembled together. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a vehicle seat assembly  10  mounted on a floor  12  of a vehicle  14 . The assembly  10  includes a vehicle seat  16  having a seat back  18  that may be movably attached, such as pivotally attached, or fixedly attached to a seat bottom  20 . The assembly  10  further includes a longitudinal seat adjustment apparatus  22  that supports the seat  16  and that is attached to the floor  12  or other portion of the vehicle  14 . 
     The seat adjustment apparatus  22  is configured to allow the seat  16  to be positioned in one or more longitudinal use positions. Referring to  FIGS. 2-3   b , the seat adjustment apparatus  22  includes a first seat support member, such as a lower rail  24 , that is attachable to the vehicle  14 , and a second seat support member, such as an upper rail  26 , that is attached to the seat bottom  20  and movable longitudinally with respect to the lower rail  24 . Although only one set of seat support members is shown in  FIG. 2 , it is to be understood that the seat adjustment apparatus  22  may include any suitable number of support members, such as one set of seat support members on each side of the seat bottom  20 . 
     The seat adjustment apparatus  22  further includes a locking device  28  for locking the seat  16  in one or more use positions, such as multiple incremental use positions. In addition, the seat adjustment apparatus  22  includes a release mechanism  30  for unlocking the locking device  28  so that the seat  16  and upper rail  26  may be moved longitudinally with respect to the lower rail  24 . 
     In the embodiment shown in  FIGS. 3   a  and  3   b , the locking device  28  includes a locking member  32  that is supported on the upper rail  26  such that the locking member  32  is movable generally vertically with respect to the rails  24  and  26  between a locked position, shown in  FIG. 3   a , and an unlocked position, shown in  3   b . For example, the locking member  32  may be supported by one or more flexible spring members  34  that are attached to the upper rail  26 . As another example, referring to  FIG. 4 , the locking member  32  may be supported by a support member, such as a pin  36 , that extends through a U-shaped bracket  38  that is attached to the upper rail  26 . In this embodiment, a coil spring  40  is disposed between the bracket  38  and a shoulder  41  on the pin  36 , such that the spring  40  urges the locking member  32  upwardly. As explained below in detail, the locking member  32  is configured to cooperate with one or more lock portions formed in the rails  24  and  26  to lock the upper rail  26  with respect to the lower rail  24  in a desired longitudinal position. 
     In the embodiment shown in  FIGS. 3   a  and  3   b , the locking member  32  is generally planar. Furthermore, in that embodiment, the locking member  32  remains generally horizontal as the locking member  32  moves between the locked and unlocked positions. 
     The release mechanism  30  may have any suitable configuration for unlocking the locking device  28 . In the embodiment shown in  FIGS. 3   a ,  3   b  and  5 , for example, the release mechanism  30  includes an external release member, such as bar  42 , connected to an internal release lever  44  that is pivotally connected to the upper rail  26  by a bracket  46 . Referring to  FIG. 3   b , when the bar  42  is raised upwardly, the release lever  44  pivots clockwise and unlocks the locking member  32  from the lower rail  24 . The release mechanism  30  may also include a spring member  48  that urges the release lever  44  counterclockwise and the bar  42  downward. 
     As another example, the seat adjustment apparatus  22  may be provided with a release mechanism (not shown) that is configured to push down on a pin  49  (or pin  36  in the embodiment shown in  FIG. 4 ) connected to the locking member  32  and that extends through the upper rail  26 , to thereby move the locking member  32  vertically with respect to the upper rail  26 . As yet another example, such a release mechanism may be provided along with the release mechanism  30 . 
     Referring to  FIGS. 6 and 7 , additional details of the rails  24  and  26  and locking member  32  will now be discussed. The upper rail  26  may be configured to slide relative to the lower rail  24  with the assistance of multiple rollers  51  disposed between the rails  24  and  26 . While the rails  24  and  26  may have any suitable construction, in the embodiment shown in  FIGS. 6 and 7 , the upper rail  26  has first and second substantially planar inner walls  50  and  52 , respectively, and first and second outer walls  54  and  56 , respectively, disposed outwardly of the inner walls  50  and  52 . The upper rail  26  further includes a first generally laterally extending section  58  that extends between the first inner wall  50  and the first outer wall  54 , and a second generally laterally extending section  60  that extends between the second inner wall  52  and the second outer wall  56 . Each section  58  and  60  includes a bent portion  62  disposed beneath a respective inner wall  50 ,  52 . 
     Each inner wall  50  and  52  has a first lock portion  64 , and each outer wall  54  and  56  has a second lock portion  66  that faces a respective first lock portion  64 . Each first lock portion  64  may include one or more first openings  68  that are each substantially formed in the associated inner wall  50 ,  52 , such that each first opening  68  is substantially planar. Furthermore, each first opening  68  is substantially located above the associated bent portion  62 . As a result, the upper rail  26  may exhibit significant strength. 
     In one embodiment, for example, at least 80% of each first opening  68  may be located above the associated bent portion  62 , wherein the above percentage is calculated by dividing the height of each first opening  68  above the bent portion  62  by the maximum height of the first opening  68 . In another embodiment, at least 85% of each first opening  68  may be located above the associated bent portion  62 . For example, approximately 87% of each first opening  68  may be located above the associated bent portion  62 . In yet another embodiment, at least 90% of each first opening  68  may be located above the associated bent portion  62 . In still yet another embodiment, at least 95% of each first opening  68  may be located above the associated bent portion  62 . In the embodiment shown in  FIG. 7 , each first opening  68  is entirely located above the associated bent portion  62 . 
     Each second lock portion  66  may include one or more second openings  70  that are aligned with the first openings  68 . As shown in  FIG. 7 , the openings  68  and  70  are spaced laterally apart from each other such that none of the second openings  70  overlap the first openings  68  when the upper rail  26  is viewed in cross section. 
     The lower rail  24  has first and second substantially planar inner walls  72  and  74 , respectively, and first and second substantially planar outer walls  76  and  78 , respectively. Each inner wall  72  and  74  has a third lock portion  80  that is located between respective first and second lock portions  64  and  66 , respectively, of the upper rail  26 . Furthermore, each third lock portion  80  may include one or more third openings  82 , such as notches. 
     When the locking member  32  is in the locked position (shown in solid lines in  FIG. 7 ), each side of the locking member  32  extends into respective first, second and third locking portions  64 ,  66  and  80 , respectively. Furthermore, in the embodiment shown in  FIG. 7 , each side of the locking member  32  does not extend into a respective third lock portion  80  when the locking member  32  is in the unlocked position (shown in dashed lines in  FIG. 7 ). Each side of the locking member  32  may also not extend into a respective second lock portion  66  when the locking member  32  is in the unlocked position. 
     Referring to  FIG. 8 , the locking member  32  may include one or more first lock features  84 , such as teeth or other projections, that extend into openings  68 ,  70  and  82  on one side of the locking member  32 , and one or more second lock features  86  that extend into openings  68 ,  70  and  82  on the other side of the locking member  32  when the locking member  32  is in the locked position. In the embodiment shown in  FIG. 8 , the locking member  32  includes multiple first openings, such as recesses or slots  88 , that define the first lock features  84 , and multiple second openings, such as recesses or slots  90 , that define the second lock features  86 . In the embodiment shown in  FIG. 8 , each first slot  88  has a first length L 1  and each second slot  90  has a second length L 2  that is substantially larger than each first length L 1  to facilitate assembly of the locking member  32  onto the upper rail  26 , as explained below in detail. For example, each second length L 2  may be at least thirty percent larger than each first length L 1 . As another example, each second length L 2  may be at least fifty percent larger than each first length L 1 . In the embodiment shown in  FIG. 8 , each second length L 2  is more than seventy-five percent larger than each first length L 1 . Furthermore, each second length L 2  may be at least one third of the width W of the locking member  32 . In the embodiment shown in  FIG. 8 , for example, each second length L 2  is greater than forty percent of the width W. 
     In the embodiment shown in  FIG. 8 , each second lock feature  86  includes a main portion that extends into a first opening  68  of the first lock portion  64 , and one or more narrower projections, such as teeth, that each extend into relatively smaller openings in the second and third lock portions  66  and  80 , respectively, when the locking member  32  is in the locked position. For example, one of the second lock  30  features  86 ′ may include a main portion  92  that extends into a first opening  68 ′ of the first lock portion  64 , and multiple projections  94  that each extend from the main portion  92  and into a respective second opening  70  of the second lock portion  66  and a respective third opening  82  of the third lock portion  80 . Furthermore, each opening  70  and  82  that receives a projection  94  associated with a particular main portion  92  is aligned with the respective first opening  68 ′ that receives the main portion  92 . 
     With the above configuration, the locking member  32  may maintain sufficient strength while also permitting efficient assembly of the locking member  32  onto the upper rail  26 . For example, because of the relatively long second slots  90  and the configuration of the upper rail  26 , the second lock features  86  of the locking member  32  may first be inserted at an angle into the corresponding first and second lock portions  64  and  66 , respectively, and then the locking member  32  may be tilted to insert the first lock features  84  into the corresponding first and second lock portions  64  and  66 , respectively, located on the opposite side of the upper rail  26 . The lower rail  24  may then be assembled onto the upper rail  26 . 
     Furthermore, because each side of the locking member  32  may extend into three lock portions  64 ,  66  and  80 , significant locking strength may be achieved. In the embodiment shown in  FIG. 8 , for example, each lock feature  84 ,  86  may be clamped by three lock portions  64 ,  66  and  80  during a crash event, thereby reducing bending moment. 
     The seat adjustment apparatus  22  may also be configured to reduce or eliminate free play in any suitable manner. For example, the leftmost first lock feature  84 ′ shown in  FIG. 8  may be wider than the other first lock features  84 , such that the leftmost first lock feature  84 ′ engages side walls  96  of the third lock portion  80  of the lower rail  24 , as shown in  FIG. 10 , when the locking member  32  is in the locked position to thereby eliminate free play between the locking member  32  and the lower rail  24 . In another embodiment, the third openings  82  of the third lock portion  80  may each be wedge shaped (e.g., one or both of the side walls forming each third opening  82  may be angled) to facilitate engagement of the leftmost first lock feature  84 ′ with the third lock portion  80 . Furthermore, referring to  FIGS. 8 and 11 , the rightmost first lock feature  84 ″ may engage angled side walls  98  of the first lock portion  64  of the upper rail  26  when the locking member  32  is in the locked position to thereby eliminate free play between the locking member  32  and the upper rail  26 . The locking member  32  may also be configured to tilt or rotate to enable the leftmost first lock feature  84 ′ to engage the lower rail  24  and the rightmost lock feature  84 ″ to engage the upper rail  26 . 
     In another embodiment shown in  FIGS. 12-15 , a locking member  32 ′ may be provided with a first pair  100  of first lock features  102  having a first spacing or pitch, and a second pair  104  of first lock features  102  having a second spacing or pitch different than the first pitch. Referring to  FIG. 15 , the second pair  104  of first lock features  102  may engage a lock feature, such as a wedge bar  106  of a first or second lock portion, of an upper rail  26 ′ when the locking member  32 ′ is in the locked position to thereby eliminate free play between the locking member  32 ′ and the upper rail  26 ′. Furthermore, the first pair  100  of first lock features  102  may engage a lock feature, such as a tooth  108  of a third lock portion, of a lower rail  24 ′ when the locking member  32 ′ is in the locked position to thereby eliminate free play between the locking member  32 ′ and the lower rail  24 ′. The locking member  32 ′ may also be configured to tilt or rotate to enable the locking member  32 ′ to engage both the lower rail  24 ′ and the upper rail  26 ′. 
     While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. For example, while the upper rail  26  in the above embodiment is provided with first and second lock portions  64  and  66 , respectively, on each side of the upper rail  26 , a longitudinal seat adjustment apparatus in accordance with the invention may instead include a lower rail with multiple lock portions on each side of the lower rail.