Abstract:
A fold-flat hinge assembly for use with a seat assembly includes an arm pivotably supported by a support member and adapted to support the seat back, as well as a gear fixedly attached to a shaft that is rotatably supported within a first slot of the support member. The shaft also includes a gear fixedly attached thereto and interfacing said arm. A blocking pin slidably supported by the support member between a first position and a second position and mechanically communicating with the shaft blocks rotation of the arm relative to the support member when in a first position. When the blocking pin is moved to a second position by the shaft interacting with the gear teeth of the arm, the arm is in rotate relative to the support member.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Technical Field  
           [0002]    The present invention relates generally to seat hinge assemblies and more particularly to a powered fold-flat seat hinge assembly.  
           [0003]    2. Discussion  
           [0004]    Vehicle markets such as mini-van and sport utility are extremely competitive and a focus for improvement by automobile manufacturers. Specifically, automobile manufacturers seek to improve the overall utility and comfort of the vehicles in these markets in pursuit of attracting and keeping customers. One particular concern of customers is the flexibility a vehicle interior maintains. Flexibility, in this sense, refers to the ability of an interior to provide seating that may be modified to suit a particular customer&#39;s needs. For example, a customer might desire the removal of a rear seat to provide increased cargo space, while maintaining a middle seat or seats for additional passengers. Additionally, a passenger might desire the seat back of a front or middle seat to fold down, providing room for cargo.  
           [0005]    While providing flexibility seats must also include features for improving occupant ease of use while maintaining safety standards. A particular ease of use feature is the mechanism by which a seat back folds forward relative to a seat. Traditional fold-forward mechanisms include manual latches that release the seat back, enabling an occupant to manually fold the seat back forward. Typically, the seat back folds flat, relative to the seat, and is held in position by the weight of the seat back itself. Further, traditional fold-forward mechanisms only provide a single fold-forward position for the seat back. Additionally, due to the manual nature of traditional fold-forward mechanisms, a vehicle occupant must have direct access to the seat back in order to operate the mechanism. For example, if a driver desired a rear seat to be folded forward, she must exit the vehicle and walk to the desired seat in order to operate the mechanism. Where powered seat hinge assemblies are provided, a first motor unlatches the arm and a second motor rotates the arm forward. This can be a prohibitively expensive and complex arrangement.  
           [0006]    It is therefore desirable in the industry to provide a fold-forward mechanism for use with a seat having a seat back that is powered, increasing the ease of use for a vehicle occupant. As such, a powered fold-forward mechanism enables an occupant to remotely fold a seat back forward without having to exit the vehicle and perform the operation manually. Further, it is desired to power the latching and rotation through a single motor.  
           [0007]    It is further desirable in the industry to provide a fold-forward mechanism for use with a seat back that enables an occupant to lock the seat back in a desired fold forward position. As such, a seat back could be folded forward while providing sufficient angle to prevent an object from sliding during braking or acceleration.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention provides a powered fold-forward mechanism for folding a seat back relative to a seat. The present invention also enables an occupant to select a desired fold-forward position for a seat back relative to a seat. Advantageously, a single motor unlatches and rotates the seat back in a cost-effective and compact assembly.  
           [0009]    A fold-forward mechanism according to the invention includes a support member and an arm pivotally supported by the support member. The arm includes a face having a plurality of gear teeth formed thereon. The support member includes a first slot rotatably supporting a gear that interfaces with the gear teeth on the arm. A blocking pin is slidably supported within a second slot of the support member and is in mechanical communication with the shaft. In a first position within the second slot, the blocking pin prevents forward rotational motion of the arm relative to the support member. The shaft is rotatable within and slidable along the first slot to enable the blocking pin to move to a second position within the second slot, in which such position the arm is free to rotate in a forward direction relative to the support member.  
           [0010]    Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a perspective view of a first preferred embodiment of a fold-flat mechanism of the present invention;  
         [0012]    [0012]FIG. 2 is a front view of the fold-flat mechanism of FIG. 1;  
         [0013]    [0013]FIG. 3 is an exploded view of the fold-flat mechanism of FIG. 1;  
         [0014]    [0014]FIG. 4 is a side view of the fold-flat mechanism of FIG. 1 in an upright position;  
         [0015]    [0015]FIG. 5 is a side view of the fold-flat mechanism in a partial forward-folded position;  
         [0016]    [0016]FIG. 6 is a side view of the fold-flat mechanism of FIG. 1 in a full-forward position;  
         [0017]    [0017]FIG. 7 is a schematic view of a seat assembly implementing the fold-flat mechanism of the present invention; and  
         [0018]    [0018]FIG. 8 is a perspective view of a second preferred embodiment of a fold-flat mechanism of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    With particular reference to FIGS. 1 and 3 a fold-flat seat hinge assembly  10 , preferably for use with a seat assembly, is shown. The fold-flat seat hinge assembly  10  includes a support bracket  12  having inner and outer brackets  14 ,  16 . The support bracket  12  rotatably supports a quadrant  18  that includes inner and outer quadrant halves  20 ,  22 .  
         [0020]    The inner and outer brackets  14 ,  16  each include a mounting hole  24 ,  25 , a sliding pin slot  26 ,  27 , a pinion slot  28 ,  29 , and a stop pin hole  34 ,  35  respectively. The inner and outer brackets  14 ,  16  are disposed on opposing sides of the quadrant  18  and a main pivot  54  is disposed through the mounting holes  24 ,  25 . The main pivot  54  initially runs through the mounting hole  25  of the outer bracket  16 , and further through the main pivot holes  32 ,  33  of the inner and outer quadrant halves  20 ,  22 , and finally through the mounting hole  24  of the inner bracket  14 . As such, the quadrant  18  is rotatably supported between the inner and outer brackets  14 ,  16  on the main pivot  54 .  
         [0021]    The inner and outer quadrant halves  20 ,  22  each include a main pivot hole  32 ,  33  and a pin slot  34 ,  35  respectively. The inner quadrant half  20  further includes a gear teeth portion  36  running along an arcuate edge  38 . The arcuate edge  38  runs along a constant radius from the center point of the main pivot hole  32 . The outer quadrant half  22  also includes an arcuate edge  40  having the same radius as the arcuate edge  38  of the inner quadrant half  20 . The arcuate edge  40  of the outer quadrant half  20  is equivalent in height to the gear teeth portion  36  of the inner quadrant half  20 . First and second spacers  42 ,  44  are included between the inner and outer quadrant halves  20 ,  22  for properly spacing and aligning the inner and outer quadrant halves  20 ,  22 . A rivet pin  83  links inner and outer quadrant halves  20 ,  22  through apertures  85 ,  87 , respectively. Preferably, the rivet pin  83  is staked to inner and outer quadrant halves  20 ,  22 . The pin slots  34 ,  35  of the inner and outer quadrant halves  20 ,  22 , respectively, are arcuate in form along a radius extending from the center of the main pivot hole  32 ,  33 . As such, the arcuate edges  38 ,  40  are concentric about the pin slots  34 ,  35 , respectively. Disposed within and running through the pin slots  34 ,  35  is a stop pin  50 , which is supported between the inner and outer brackets  14 ,  16  by the stop pin holes  30 ,  31 . As the quadrant  18  rotates about the main pivot  54 , the stop pin  50  runs within the pin slots  34 ,  35  of the inner and outer quadrant halves  20 ,  22 . A range for rotational movement of the quadrant  18  relative to the bracket  12  is established by the arcuate range of the stop pin  50  within the pin slots  34 ,  35 .  
         [0022]    A pinion shaft  56  is disposed between the inner and outer brackets  14 ,  16  and runs through the pinion slots  28 ,  29  of the inner and outer brackets  14 ,  16 , respectively. The pinion slots  28 ,  29  are arcuate in form sharing a common radial center point as the arcuate edges  38 ,  40  and the pin slots  34 ,  35  of the inner and outer quadrant halves  20 ,  22 . As such, the pinion slots  28 ,  29  are concentric about both the arcuate edges  38 ,  40  and the pin slots  34 ,  35 . The pinion shaft  56  is also rotatably supported through the holes  61 ,  63  of the first and second lever arms  60 ,  62 , respectively.  
         [0023]    The pinion shaft  56  includes first and second cylindrical extensions  53 ,  55 , first and second key surfaces  57 ,  59  disposed therebetween and a radially extending collar  51 . The first cylindrical extension includes a bearing surface  49 . A pinion gear  58  is supported by and fixed for rotation with the pinion shaft  56  and meshes with the gear teeth portion  36  of the inner quadrant half  20 . The pinion shaft  56  is received through a centrally disposed aperture  48  of the pinion gear  58 , wherein the key surfaces  57 ,  59  interface with corresponding key surfaces of the aperture  48 . The collar  51  prohibits the pinion shaft  56  from sliding completely through the aperture  48 , thus retaining the pinion gear  58  on the pinion shaft  56 . A shaft sleeve  64  is included and is rotatably supported by the pinion shaft  56  on the bearing surface  49  of the first cylindrical extension  53 . The outside surface  65  of the shaft sleeve  64  contacts and slidably supports the arcuate edge  40  of the outer quadrant half  22  (see FIG. 2). The first and second lever arms  60 ,  62  are disposed on either side of the inner and outer quadrant halves  20 ,  22 , respectively, and are rotatably supported by the main pivot  54 . As such, the first and second lever arms  60 ,  62  are concentrically aligned and rotatable about the same pivot point as the quadrant  18 .  
         [0024]    First and second link arms  66 ,  68  link the first and second lever arms  60 ,  62  with a sliding pin  70 . A first end of each of the first and second link arms  66 ,  68  is rotatably attached to second ends of the first and second lever arms  60 ,  62  via first and second link rivets  71 ,  72 , each of which is disposed through a pair of aligned apertures  75 ,  77  of the first and second lever arms  60 ,  62  and the first and second line arms  66 ,  68 , respectively. A second end of each of the first and second link arms  66 ,  68  is rotatably attached to the sliding pin  70  via holes  67 ,  69 , respectively. The sliding pin  70  is disposed between the inner and outer brackets  14 ,  16  and runs along vertical sliding pin slots  26 ,  27 .  
         [0025]    In a first preferred embodiment, the fold-flat seat hinge assembly  10  is operated by an electric motor  74 . A cable shaft  76  is a flexible shaft operably connected at a first end to an end of the second cylindrical extension  55  of the pinion shaft  56  and to the electric motor  74  at a second end. A flexible cable shaft  76  allows the ends of the shaft  76  to be misaligned or slid in slots  28 ,  29  of the inner and outer brackets  14 ,  16  while rotating the pinion shaft  56 . The electric motor  74  selectively rotates the cable shaft  76 , which in turn rotates the pinion shaft  56 . The electric motor  74  is selectively operable in forward, reverse, and stop modes by an operator through a switch (not shown). Additionally, an electric power source (not shown), such as a battery, is included to power the electric motor  74 .  
         [0026]    With particular reference to FIGS. 4 through 6, operation of fold-flat seat hinge assembly  10  will be described in detail. It should be first noted however, that FIGS. 4 through 6 are side views of the fold-flat seat hinge assembly  10  with the inner bracket  14  removed for clarity. Initially, as shown in FIG. 4, the quadrant  18  is in a first upright position relative to the outer bracket  16 . The sliding pin  70  is located in a first position at the upper most point of the sliding pin slots  26 ,  27 . In this position, the sliding pin  70  prevents forward rotation of the quadrant  18  relative to the bracket  12  by blocking the stop faces  78 ,  79  of the inner and outer quadrant halves  34 ,  35 . In the initial position, the pinion shaft  56  and the pinion gear  58  are positioned at the lowest end of the pinion slots  28 ,  29  and the stop pin  50  is located at the lowest point of the pin slots  34 ,  35 .  
         [0027]    A fold-forward process is initiated by triggering the switch to operate the electric motor  74  in the forward mode. The electric motor  74  rotates the cable shaft  76 , further rotating the pinion shaft  56  and the pinion gear  58 . Because the quadrant  18  is prevented from forward rotation by the sliding pin  70  the pinion gear  58  rotates along the gear teeth portion  36  of the inner quadrant  20 . The pinion gear  58  and the pinion shaft  56  slide toward an upper portion of the pinion slots  28 ,  29 . As a result, the first and second lever arms  60 ,  62  begin to rotate upwards with the pinion gear  58  and the pinion shaft  56 . As the first and second lever arms  60 ,  62  rotate upward, the first and second link arms  66 ,  68  are pushed downward thus pushing the sliding pin  70  in a downward direction within the sliding pin slots  26 ,  27 .  
         [0028]    As best seen in FIG. 5, once the pinion shaft  56  and the pinion gear  58  have reached the upper portion of the pinion slots,  28 ,  29 , the sliding pin  70  is sufficiently below stop faces  78 ,  79  wherein the quadrant  18  is free to rotate in a forward direction. Continued rotation of the pinion gear  58  by the electric motor  74  causes the quadrant  18  to rotate forward until a fold-flat position has been achieved. This is best seen in FIG. 6. Once the fold-flat position has been achieved, the stop pin  50  is positioned at an upper portion of the pin slots  34 ,  35 . Also, the stop pin  50  is located within the recesses  80 ,  82  of the first and second lever arms  60 ,  62 , respectively. It should also be noted that the electric motor  74  could be switched to a stop mode during the fold-flat process, holding the seat back at a desired angle relative to the seat.  
         [0029]    In a reverse mode, the electric motor  74  drives the pinion shaft  56  and the pinion gear  58  in a reverse direction. Initially, the arcuate edges  38 ,  40  of the quadrant  18  slidably contact the sliding pin  70 , thus prohibiting upward movement of the sliding pin  70 . As a result, the pinion shaft  56  and the pinion gear  58  remain positioned in the upper portion of the pinion slots  28 ,  29  until the pinion gear  58  has rotated the quadrant  18  sufficiently, wherein arcuate edges  38 ,  40  no longer block upward movement of the sliding pin  70 . Due to the continued rotation of the pinion gear  58  on the gear teeth portion  36  of the inner quadrant half  14 , the pinion gear  58  and the pinion shaft  56  slide downward toward a lower portion of the pinion slots  28 ,  29 . As this occurs, the first and second lever arms  60 ,  62  rotate downward, thus pulling the first and second link arms  66 ,  68  upward. As the first and second link arms  66 ,  68  are drawn upward, the sliding pin  70  travels upward within the sliding pin slots  26 ,  27 . The electric motor  74  and the pinion gear  58  continue to drive the quadrant  18  to its initial upright position until the stop pin  50  prevents further rotation of the quadrant  18 . This is achieved by the stop pin  50  contacting the lower portion of the pin slots  34 ,  35 .  
         [0030]    With particular reference to FIG. 7, a seat assembly  100  is shown implementing the fold-flat seat hinge assembly  10 . The seat assembly  100  includes a seat  102  and seat back  104 . The seat back  104  is attached to and supported by the quadrant  18  and is pivotally adjustable relative to the seat  102  by the fold-flat seat hinge assembly  10 . The seat back  104  pivots with the quadrant  18  as the quadrant  18  is caused to pivot as described above. However, it is important to note that while the seat back  104  is located in an upright position relative to the seat  102 , forward pivoting of the quadrant  18  is prohibited by the sliding pin  70 . In this manner, occupant safety is increased as the quadrant  18 , and therefore seat back  104 , are prohibited from unintentional forward pivoting (e.g., in the event of an accident).  
         [0031]    It is also foreseen that the fold-flat seat hinge assembly  10  may be manually operated. With reference to FIG. 8, a second preferred embodiment of the fold-flat seat assembly  10  includes a dial  110  for manually rotating the pinion shaft  56  and the pinion gear  58 . The dial  110  is fixedly attached to the second end of the pinion shaft  56 . The second preferred embodiment is similar in operation as the first preferred embodiment described above.  
         [0032]    While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the description of the appended claims.