Abstract:
A door bracket is mounted to a vehicle sliding door. A primary track is mounted along a side and extends to a remote end. A roller bracket having rollers received by the primary track is movable between a first position proximate the opening and a second position at the remote end. A link is pivotally joined to the roller bracket by a first pivot and pivotally joined to the door bracket by a second pivot. The link is rotatable around the first pivot between a first orientation and a second orientation. The link comprises an extension arm extending from the link toward the primary track. A shift mechanism contacts the extension arm when the roller bracket is at an intermediate trip point so that the link shifts from its first orientation to its second orientation when the sliding door is being opened.

Description:
BACKGROUND OF INVENTION 
       [0001]    The present invention relates generally to vehicular sliding doors in which the rearward side of the sliding door is supported by a roller bracket that traverses a roller track mounted along the exterior side of the vehicle. 
         [0002]    A typical sliding door for a passenger vehicle such as a van, minivan, or a crossover vehicle is supported and guided by upper and lower roller bracket assemblies at the front edge of the sliding door and a center roller bracket assembly attached to the rear edge of the door. 
         [0003]    The size of the door opening that may be uncovered when the sliding door opens is limited to the available distance of rearward travel for the door. A large door opening is desired for ease of ingress/egress and for maximizing the size of loads that may pass through the door opening. However, door travel is typically limited by the length of the tracks in which the roller bracket assemblies traverse during opening of the sliding door. The center track, which receives a roller bracket mounted to the rearward edge of the sliding door, cannot extend beyond the back edge of the vehicle body. The presence of rear taillight assemblies may further limit the available space for the center track. In addition, it is desired to minimize the length of the track to reduce its visibility for aesthetic purposes. Therefore, the open door space for ingress/egress in prior art vehicles has been undesirably limited. 
       SUMMARY OF INVENTION 
       [0004]    In order to extend the travel of the sliding door beyond the position that would otherwise result when the roller bracket reaches the end of the track, a link joining the roller bracket to the door pivots to a different orientation under control of a shift mechanism as it moves past an intermediate trip point, adding to the opening distance traversed by the sliding door. 
         [0005]    Thus, in one aspect of the invention, an apparatus is provided for supporting a sliding door that moves between a closed position and a fully open position to selectively cover an opening in a vehicle. A door bracket fixedly mounts to the sliding door. A primary track is mounted along an exterior side of the vehicle and extends away from the opening to a remote end. The length of the primary track from the opening to the remote end is less than the distance traveled by the sliding door between the closed position and the fully open position. A roller bracket having rollers received by the primary track is movable between a first position proximate the opening and a second position at the remote end of the primary track. A link is pivotally joined to the roller bracket by a first pivot and pivotally joined to the door bracket by a second pivot. The link is rotatable around the first pivot between a first orientation for positioning the sliding door toward its closed position and a second orientation for positioning the sliding door toward the fully open position. The link comprises an extension arm extending from the first pivot on the link generally toward the primary track. A shift mechanism contacts the extension arm when the roller bracket is at an intermediate trip point between the first position and the second position so that the link shifts from its first orientation to its second orientation when the sliding door is being opened and so that the link shifts from its second orientation to its first orientation when the sliding door is being closed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0006]      FIG. 1  is a perspective view showing a vehicle with a sliding door in the closed position. 
           [0007]      FIG. 2  is a diagram showing the relationship between door opening size and sliding door travel for a vehicle body having a particular length. 
           [0008]      FIG. 3  is a perspective view showing a first embodiment of a sliding door support apparatus of the invention. 
           [0009]      FIG. 4  is a top view showing a roller bracket at the closed position in a track. 
           [0010]      FIG. 5  is a top view showing the roller bracket near the fully open position in the track. 
           [0011]      FIG. 6  is a bottom view showing progressive movement of the roller bracket and shifting of the extension arm at different positions along the track. 
           [0012]      FIG. 7  is a bottom view showing a primary track and a substantially parallel secondary track having an asymptotic shape. 
           [0013]      FIG. 8  is a cross-sectional view showing the door support apparatus and the tracks with the roller bracket at an intermediate trip point. 
           [0014]      FIG. 9A  is a perspective view showing a supplemental shift mechanism at the intermediate trip point. 
           [0015]      FIG. 9B  is a diagram showing operation of the shift mechanism of  FIG. 9A . 
           [0016]      FIG. 10  shows an alternative embodiment of the shift mechanism utilizing a cup. 
           [0017]      FIG. 11  shows an alternative embodiment of the shift mechanism utilizing a rocker bar. 
           [0018]      FIG. 12  shows an alternative embodiment of the shift mechanism utilizing a pin. 
           [0019]      FIG. 13  shows an alternative embodiment of the shift mechanism utilizing a spring latch. 
           [0020]      FIG. 14  shows an alternative embodiment of the shift mechanism utilizing a frictional surface. 
           [0021]      FIG. 15  shows an alternative embodiment of the shift mechanism utilizing a gear rack. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Referring now to  FIG. 1 , a vehicle  10  has a sliding door  11  supported along an upper roller track  12 , a lower roller track  13 , and a center roller track  14 . Respective roller brackets (not shown) slidable in each track are joined to respective door brackets (not shown) on the interior side of sliding door  11 . In a conventional system, a pair of brackets at the top and bottom of the forward edge of sliding door  11  are joined to the roller brackets sliding in tracks  12  and  13 , respectively. A door bracket attached at the center rear edge of sliding door  11  is coupled to a roller bracket slidably received in track  14 . The tracks have initial portions which move radially outward so that the door first moves outward from the vehicle body in order to clear the vehicle body and then slides toward the rear of vehicle  10 . Because of this compound movement, each roller bracket is pivotally connected to its respective door bracket. 
         [0023]    Sliding door  11 , and the opening in vehicle  10  which receives sliding door  11 , each have a front-to-back width designated D 1 . For conventional sliding doors, the rearward movement of sliding door  11  has a maximum distance designated D 2  which is the length of center track  14  from the edge of the door opening to the end of track  14 . The space available for track  14  is limited by the overall length of vehicle  10 , and may be even more limited by the presence of other structures such as a taillight  15 . If distance D 2  is less than distance D 1 , then when a conventional sliding door  11  is at its maximum rearward travel position it continues to block a portion of the door opening. It would be desirable to obtain an extension of the sliding door travel without increasing the length of the corresponding center track. 
         [0024]    As shown in  FIG. 2 , vehicle  10  may have a side passenger opening  16  allowing ingress/egress to and from seats  17 . In the upper half of  FIG. 2 , opening  16  is sufficiently small compared to the length of the vehicle behind opening  16  that a center track  18  can be accommodated on vehicle  10  to allow opening of the sliding door to a position  19  using conventional door sliders. In the lower half of  FIG. 2 , a larger (i.e., wider) opening  16 ′ allows easier ingress and egress to rear seat  17 . However, the remaining length of the vehicle for accommodating track  18 ′ is insufficient. Therefore, the sliding door cannot be moved to a desired position  19 ′ using the conventional sliding door support apparatus. Track  18 ′ would need to extend through area  20  in order to provide a wider door opening  16 ′. 
         [0025]    The present invention incorporates a link between a door mounted hinge and a body-side roller bracket to allow extended travel of the sliding door beyond the end of the track. The invention incorporates a mechanism to ensure the transition of the link orientation from forward facing to rearward facing during sliding door travel, thereby providing a smooth and easy operation of the sliding door. 
         [0026]    As shown in  FIG. 3 , a door bracket  21  for affixing to an interior side of a sliding door (not shown) is joined to a roller bracket  22  by a link  23 . The connections of link  23  to door bracket  21  and roller bracket  22  are pivot connections using pivot pins  24  and  25 , respectively. Link  23  has an extension arm  26  which extends from pivot  25  of link  23  generally toward the primary track. Preferably, extension arm  26  is integrated or continuous with link  23 , such as by a single metal stamping. Extension arm  26  has a roller  30  that engages a secondary track to control the link orientation. Roller bracket  22  carries rollers  31 ,  32 , and  33  for traversing a primary track as is described below. 
         [0027]      FIGS. 4 and 5  are top views showing the door support apparatus in two different locations along a primary track  27 . In  FIG. 4 , roller bracket  22  is in an initial portion of primary track  27  which is radially sloped toward the interior of the vehicle so that the sliding door may have an outward motion from its closed position. Due to the pivot connection between door bracket  21  and link  23 , the longitudinal surface of door bracket  21  always remains substantially parallel to the side of the vehicle. Link  23  is pivoted such that the sliding door is positioned toward its closed position when roller bracket  22  is in this initial position. 
         [0028]    As shown in  FIG. 5 , after the sliding door has been brought toward the rear end of track  27 , link  23  is reoriented to a second orientation for positioning the sliding door toward the fully open position by interaction of extension arm  26  with secondary track  28 . 
         [0029]      FIG. 6  provides a bottom view showing the interaction of extension arm  26  with secondary track  28  for reorienting link  23  as roller bracket  22  progressively moves in primary track  27  in either direction. Because of pivot connection  24 , door bracket  21  maintains an alignment substantially parallel to the side of the vehicle. Secondary track  28  is substantially parallel with primary track  27 , but has a slightly asymptotic shape with a maximum separation from primary track  27  at an intermediate trip point  35 . At intermediate trip point  35 , link  23  is halfway between the first and second orientations corresponding to the fully closed and fully opened door orientations. By providing a gradual reorientation of the link, smooth door operation is obtained. 
         [0030]      FIG. 7  shows an alternative embodiment of secondary track  28  with an asymptotic shape providing intermediate trip point  35  at a single point of maximum separation between the tracks (shown at a greatly exaggerated scale for the purpose of showing the overall shape with greater clarity). The asymptotic shape of secondary track  28  creates a shift mechanism for contacting the extension arm to shift the link between its first and second orientations. 
         [0031]      FIG. 8  shows in cross-section the sliding door support apparatus and the vehicle tracks mounted to a vehicle. A fastener  36  mounts door bracket  21  to a sliding door (not shown). The vehicle has a track space  37  behind a body panel  38  for mounting tracks  27  and  28  to the vehicle by a fastener  39 . Thus, roller bracket  22  can freely slide rearward and forward along track  27  while supporting the weight of the door. Moreover, the changing separation between the paths of the rollers within primary and secondary tracks  27  and  28  (as projected onto a horizontal plane) controls the orientation of link  23 , as described above. 
         [0032]    For increased robustness, an additional shift mechanism may be utilized as shown in  FIG. 9A . When roller  30  of extension arm  26  is at intermediate trip point  35  where it has its maximum separation from the path of the primary track, an assist rocker  40  mounted for pivotal movement on a pin  41  temporarily restrains roller  30  to ensure a coordinated transition between front-facing and rear-facing orientations. A counter-rotating assist rocker  42  mounted for pivotal movement on a pin  42  and interlocking with assist rocker  40  is displaced by contact with roller  31  to control the capture and release of roller  30 . A detent mechanism (not shown) would preferably keep rockers  40  and  42  in place when the rollers are not engaged. 
         [0033]      FIG. 9B  shows the stages of the function of rockers  40  and  42 . Although the pivot axes of rockers  40  and  42  are preferably perpendicular, they are shown as parallel in  FIG. 9B  to better visualize their operation. In the opening process, as roller  30  nears the intermediate trip point  35 , it is restrained from further travel in the opening direction by rocker  40 , as shown on the right side of  FIG. 9B . Rocker  40  is held by rocker  42  in this initial position, which is in turn restrained by roller  31 . As roller  31  reaches intermediate trip point  35  (as shown in the center panel of  FIG. 9B ), it causes rocker  42  to rotate while restraining roller  30 . As roller  31  translates further in the opening direction, it causes rocker  42  to move into its second position, which in turn causes rocker  40  to rotate into its second position, releasing roller  30  to continue in the opening direction but preventing it from traveling in the closing direction, thereby assuring proper transition of the extension arm  26  from its first orientation to its second orientation. 
         [0034]    Other shift mechanisms can be located at the intermediate trip point for re-orienting the link. As shown in  FIG. 10 , a rotating cup  45  may be mounted to a support block  46  at or adjacent to the intermediate trip point (e.g., just below the primary track) for interfacing with extension arm  26 . As extension arm  26  moves toward cup  45 , it is captured in cup  45  and pushes against the side of cup  45 . The only movement of cup  45  is rotation over a limited range. Thus, as the roller bracket continues to move, extension arm  26  is forcibly reoriented by the reaction of cup  45 . Cup  45  eventually rotates to a new position  45 ′ so that extension arm  26  can escape after it has been reoriented. The same cup position is maintained so that extension arm  26  can be again captured when moving back in the opposite direction. A detent  47  is provided on block  46  for providing resistance against rotation of cup  45  between its two positions, and thereby both maintaining the desired position of cup  45  when extension arm is not present, and adding to the resistance that causes extension arm  26  to reorient. 
         [0035]      FIG. 11  shows a rocker bar  50  which operates similarly to the cup. Rocker bar  50  is pivotally mounted on a pivot pin  51  on a block  52 . Rocker bar  50  includes a detent feature  53  for interacting with a mating detent feature  54  on block  52 , thereby providing two preferred positions for rocker  50  as shown at  50  and  50 ′. When extension arm  26  moves past the intermediate trip point, it interfaces with rocker bar  50  which provides the necessary force for reorienting extension arm  26 . As shown in  FIG. 12 , a rigid pin  55  mounted to a block  56  at the intermediate trip point may also be used to interface with extension arm  26 ; however, the reorientation of extension arm  26  may operate less smoothly. 
         [0036]    As shown in  FIG. 13 , a pair of spring loaded extensions  60  and  61  mounted with an intervening gap  63  on a mounting block  62  at the intermediate trip point can also be provided for reorienting extension arm  26  by means of a spring latch. The end surfaces of extensions  60  and  61  are ramped so that as extension arm  26  approaches the intermediate trip point, the first extension is compressed against its spring allowing extension arm  26  to enter gap  63 . Once in the gap, extension arm  26  contacts the non-ramped surface of other extension so that extension arm  26  has to pivot before it can clear the extension.  FIG. 14  shows another embodiment wherein a block  65  at the intermediate trip point includes a frictional surface  66  that tends to slow the movement of extension arm  26 , thereby causing it to rotate as it moves past the intermediate trip point. 
         [0037]    A gear rack may also be used for the shift mechanism as shown in  FIG. 15 . Extension arm  26  has a plurality of gear teeth  67  formed therein. At the intermediate trip point, gear teeth  67  interact with fixed gear teeth  68  on a fixed gear rack  69  so that extension arm  26  rotates in the manner desired to reorient the link between the first and second orientations. 
         [0038]    While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.