Abstract:
A linear recliner assembly is provided having a recliner rod slidably supported within a housing. The recliner rod is selectively engageable with a pawl which is fixed within the housing. The recliner rod is in contact with a cam which is operable to force the recliner rod into engagement with the pawl or enable the recliner rod to fall out of engagement with he pawl. The cam is biased in a first position by a biasing mechanism, such that the recliner rod is engaged with the pawl. The linear recliner assembly is implemented into a seat assembly for enabling an operator to select a plurality of recline positions of a seat back relative to a seat.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a divisional of U.S. patent application Ser. No. 09/748,482 filed on Dec. 27, 2000. The disclosure of the above application is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to linear recliner assemblies and more particularly to a linear recliner assembly having a fixed pawl.  
         BACKGROUND OF THE INVENTION  
         [0003]    Occupant safety and comfort are paramount concerns for automobile manufacturers. In particular, vehicle seating systems are a significant focus for improved comfort and safety. Conventional vehicle seating systems include reclining seats that enable comfort adjustment by a vehicle occupant.  
           [0004]    In reclining seats, a recliner assembly is mounted to a long lever arm, namely the seat back, against which various forces are applied. The recliner assembly in a vehicle seat is quite small when compared with the length of a seatback, and vehicle vibration or movement of an occupant may impose various forces upon that lever arm during use. Because these forces are applied along such a lengthy lever arm, they can impose a large moment about the recliner assembly&#39;s pivot point potentially overcoming the capability of the assembly to anchor the seatback.  
           [0005]    In addition, any imperfections in the components of the recliner assembly, such as play or backlash between the engaging teeth or tolerances in the assembly components, may allow the seatback to move a miniscule amount even when the assembly is locked. These small excursions are magnified by the length of the lever arm and become noticeable at the upper end of the seatback. For example, the seatback of an unoccupied seat may tend to oscillate when the vehicle encounters rough road conditions. This magnified play in a recliner assembly has been termed “chucking” and refers to any imperfection or play in the assembly components that allows movement of the lever arm or seatback while the assembly is in a locked condition.  
           [0006]    Therefore, it is desirable in the industry to provide a recliner assembly that significantly reduces or eliminates chucking of a seat assembly. It is further desirable that such a recliner assembly be sufficiently strong, providing adequate occupant protection in the event of an accident.  
           [0007]    It is also desirable in the industry to reduce the overall complexity of traditional reclining assemblies while maintaining operation and safety standards. In this manner, overall cost is reduced through implementation of fewer components and improved manufacturability. Additionally, a weight savings can be achieved through the utilization of fewer components in the reclining assembly.  
         SUMMARY OF THE INVENTION  
         [0008]    Accordingly, a simplified linear recliner assembly according to the present invention overcomes the above described deficiencies of present linear recliner assemblies. Specifically, the linear recliner assembly of the present invention includes fewer components and a less complex overall design than previous linear recliner assemblies.  
           [0009]    The linear recliner assembly of the present invention includes a housing, a recliner rod slidably supported within the housing, a pawl supported by the housing, and a cam rotatably supported by the housing. The cam has a cam surface that slidably interfaces the recliner rod. The cam is rotatable for selectively engaging the recliner rod with the pawl such that the recliner rod is prohibited from linear movement when engaged with the pawl. Preferably, the cam is biased in a first direction of rotation to force the recliner rod into engagement with the pawl. The cam is rotatable against the biasing force to disengage the recliner rod from the pawl for linear adjustment of the recliner rod relative to the housing.  
           [0010]    Some advantages of the linear recliner assembly of the present invention include improvements in cost, weight and manufacturability of the linear recliner assembly.  
           [0011]    A further advantage of the present invention is a simple, compact construction that reduces tolerance stack-up that would otherwise result in significant seat back chucking.  
           [0012]    Additionally, packaging and trim of the overall seat assembly is more easily achieved because the recliner assembly&#39;s moving parts are internal to the compact housing.  
           [0013]    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  
       [0014]    [0014]FIG. 1 is a side view detailing components of a linear recliner assembly according to the present invention;  
         [0015]    [0015]FIG. 2 is a top view of the linear recliner assembly of FIG. 1;  
         [0016]    [0016]FIG. 3 is a side view of the linear recliner assembly of FIG. 1, showing the linear recliner assembly is a disengaged state;  
         [0017]    [0017]FIG. 4 is a side view detailing components of a second preferred embodiment of the linear recliner assembly; and  
         [0018]    [0018]FIG. 5 is a schematic view of a seat assembly implementing the linear recliner assembly of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    With reference to FIGS. 1 through 3, a preferred embodiment of a linear recliner assembly  10  will be described in detail. The linear recliner assembly  10  includes a housing  12  that includes a first support plate  14  and a second support plate  16 . A recliner rod  18  is slidably supported within the housing  12  and includes a toothed rack  20  formed in a top face  22 . A pawl  24  is supported within the housing  12  and has a tooth portion  26  on a surface  28  facing the toothed rack  20  of the reclining rod  18 . The pawl  24  is fixed between the first and second support plates  14 , 16  to prohibit pivoting or other movement relative to the housing  12 . A cam  30  is rotatably supported between the first and second support plates  14 , 16  and has a cammed surface  32  that contacts a bottom face  34  of the recliner rod  18 . The cam  30  is fixed for rotation with a spindle  36 , which is rotatably supported by the first and second support plates  14 , 16  through respective openings  38 , 40 . The spindle  36  includes a splined portion  42  at a distal end, to which a handle or lever  44  may be attached (see FIG. 5).  
         [0020]    The cam  30  is rotatable between a first and second position. In a first position, the cam  30  forces the recliner rod  18  into engagement with the pawl  24 . Specifically, the cam  30  pushes against the bottom surface  34  of the recliner rod  18  to force the toothed rack  20  of the recliner rod  18  and the tooth portion  26  of the pawl  24  to engage. In this position, the recliner rod  18  is prohibited from linear movement relative to the housing  12 . The cam  30  is rotatable to a second position wherein the recliner rod  18  disengages the pawl  24 . In this position, the recliner rod is free to move linearly relative to the housing  12 .  
         [0021]    Preferably the recliner rod  18  remains in the engaged position until an operator disengages the recliner rod  18  in order to adjust a respective seat assembly (see FIG. 5). Accordingly, the cam  30  is preferably biased in the first position by a biasing mechanism  46 . In a first preferred embodiment, the biasing mechanism  46  includes a biasing rod  48  that includes a cylindrical portion  50 , a collar  52  disposed intermediately along the cylindrical portion  50 , and a ball  54  formed at distal end of the cylindrical portion  50 . The biasing rod  48  is slidably supported within a guide bracket  56 , which is supported by the housing  12 . The guide bracket  56  includes a seat area  58  and an opening  60  through which the cylindrical portion  50  of the biasing rod  48  is disposed. A biasing spring  62  is disposed about the cylindrical portion  50  between the collar  52  and the seat area  58  of the guide bracket  56 . The biasing spring  62  biases the biasing rod  48  away from the guide bracket  56 . The ball  54  of the biasing rod  48  seats within a socket  64  of the cam  30 . The relationship between the ball  54  and socket  64  interface of the biasing rod  48  and cam  30  is similar to that of a conventional ball and socket joint. As best seen if FIG. 1, the biasing mechanism  46  holds the cam  30  in the first position wherein the recliner rod  18  is engaged with the pawl  24 .  
         [0022]    To disengage the recliner rod  18  from the pawl  24 , an operator rotates the spindle  36 , and thus the cam  30 , against the biasing force of the biasing mechanism  46 . The rotation of the cam  30  causes the biasing rod  48  to be pushed toward and/or through the guide bracket  56 , thereby compressing the biasing spring  62 , which is seated between the collar  52  and the seat area  58  of the guide bracket  56 . Additionally, as the cam  30  rotates to the second position, the ball  54  of the biasing rod rotates within the socket  64  of the cam  30 . As best seen in FIG. 2, when the cam  30  is sufficiently rotated against the biasing force of the biasing mechanism  46 , the recliner rod  18  is free to fall out of engagement with the pawl  24  and the recliner rod  18  may move linearly with respect to the housing  12 . In this manner, the recliner rod  18  can be linearly adjusted with respect to the housing  12 .  
         [0023]    With particular reference to FIG. 4, a second preferred embodiment of the linear recliner assembly  10  will be described in detail. It should be noted that the second preferred embodiment includes essentially the same components as the first preferred embodiment and, therefore, like reference numerals will be used to identify identical components.  
         [0024]    In the second preferred embodiment, the linear recliner assembly  10  includes a coil spring  70  for biasing the spindle  36  in a first rotational direction, such that the cam  30  acts upon the recliner rod  18  to engage the recliner rod  18  with the pawl  24 . The coil spring  70  includes a first end  72  that is received in a slot  74  of the spindle  36 ′. The coil spring  70  is disposed about the spindle  36 ′ and further includes a second end  76  that is held by a bracket  78  formed within the housing  12 .  
         [0025]    To disengage the recliner rod  18  from the pawl  24 , the cam  30  is rotated in a second rotational direction, against the biasing force of the coil spring  70 . When the cam  30  is sufficiently rotated, the recliner rod  18  disengages the pawl  24 , whereby the recliner rod  18  may move linearly with respect to the housing  12 . In this manner, the recliner rod  18  can be linearly adjusted with respect to the housing  12 .  
         [0026]    With particular reference to FIG. 5 a seat assembly  100  implementing the linear recliner assembly  10  will be described in detail. It should be noted that either the first or second preferred embodiment of the linear recliner assembly  10  can be implemented in the seat assembly  100 . The seat assembly  100  generally includes a seat  102  and a seat back  104  that is pivotal relative to the seat  102 . A support arm  106  is disposed within the seat back for supporting the seat back  104  relative to the seat  102 . The support arm  106  is pivotally attached to a support bracket  108  about an axis Q. A coil spring  110  is disposed about axis Q for biasing the support arm  106  in a first rotational direction relative to the support bracket  108 . The recliner rod  18  includes an attachment point  112  for pivotally attaching the recliner rod  18  to an end of the support arm  106 . As the recliner rod  18  is caused to move linearly with respect to the housing  12 , the linear motion of the recliner rod  18  translates into pivotal motion of the support arm  106  about the axis Q. In this manner, an operator is able to select a desired recline position of the seat back  104  relative to the seat  102 . Further, the coil  110  preferably biases the support arm  106 , and thus the seat back  104 , toward the seat  102 . Thus, when the recliner rod  18  is disengaged from the pawl  24 , the seat back  104  rotates toward the seat  102 , absent any opposing force such as a seated occupant.  
         [0027]    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.