Abstract:
A fold down seat back has a lumbar support device in it. A traction cable is operatively engaged at one end with the lumbar support device to actuate it. The fold down seat back includes a rotating cable tension unit and a fixed torsion bar. The rotating member moves relative to the fixed member when said fold down seat back is folded down. The traction cable is comprised of a sleeve having a first end and a second end and a wire having a first end and a second end. The wire is disposed to slide axially through the sleeve. The first sleeve end is attached to the rotating cable tension unit. The wire end is attached to the fixed torsion bar. The wire end may be attached to the torsion rod with a pulley. These attachments of the sleeve end and the wire end cause the wire to be drawn axially through the sleeve when the seat back is folded up, extending a lumbar support, and cause the wire to be relaxed when the seat back is folded down, flattening the lumbar support.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    None.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    This invention is in the field of lumbar supports for automobiles.  
           [0005]    2. Related Art  
           [0006]    Lumbar supports for automobile seats are a known and popular ergonomic option. Whether lumbar supports are static or variable, their effect depends upon the creation of depth in the portion of the seat positioned to correspond to the passenger&#39;s lumbar spine.  
           [0007]    Another popular feature in vehicles having cargo space such as sport utility vehicles, station wagons and the like, is fold down rear seats. Folding these seats down increases the cargo space. For that purpose, it is advantageous that the seat backs for the fold down rear seats be as thin as possible in their down position. Any reduction in the depth of the seat back when it is folded down increases the amount of available cargo space above it.  
           [0008]    Hence, there is a need in the industry for a fold down rear seat back that has depth in the lumbar area when in its up position and is as thin as possible when in its down position.  
         SUMMARY OF THE INVENTION  
         [0009]    It is in view of the above problems that the present invention was developed. The present invention is a fold down rear seat back for a motor vehicle that has depth in the lumbar area when in its up position, and automatically reduces that depth when folded down into its folded position.  
           [0010]    A lumbar support device is in a fold down seat back. A traction cable is operatively engaged at one end with the lumbar support device. The fold down seat back includes a rotating member and a fixed member. The fixed member may be a torsion bar. The rotating member may be a mount, a cable tension unit, or other device operatively engaged with the other end of the traction cable and with the fixed member. The rotating member moves relative to the fixed member when said fold down seat back is folded down. The traction cable is comprised of a sleeve having a first end and a second end and a wire having a first end and a second end. The wire is disposed to slide axially through the sleeve.  
           [0011]    The first sleeve end is attached to one of the fixed member or the rotating member; the first wire end is attached to the other member. The wire end may be attached to the torsion rod with a pulley. These attachments of the sleeve end and the wire end cause the wire to be drawn axially through the sleeve when the seat back is folded up, extending a lumbar support, and cause the wire to be relaxed when the seat back is folded down, flattening the lumbar support when the seat back is down.  
           [0012]    Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings:  
         [0014]    [0014]FIG. 1 is an isometric view of the automatic lumbar support as installed in a seat frame.  
         [0015]    [0015]FIG. 2 is a schematic front view of the automatic lumbar support.  
         [0016]    [0016]FIG. 3 is a top view of the automatic lumbar support.  
         [0017]    [0017]FIG. 4 is a side view of the automatic lumbar support.  
         [0018]    [0018]FIG. 5 is a cutaway detail of the cable tension unit. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    Referring to the accompanying drawings in which like reference numbers indicate like elements, FIG. 1 is an isometric view of the automatic lumbar support for a fold down seat back of the present invention. Seat back frame  10  is hingedly connected to a seat bottom frame (not shown) at connection  12 . Although other connections between seat backs and seat bottoms are possible, it is common for a hinge connection such as that depicted to include a torsion bar  14 . It is also common for a torsion bar  14  to be fixed such that it remains stationary at all positions of the seat back, and does not move when the seat back moves. Lumbar support  20  is mounted on seat frame  10 .  
         [0020]    It is appreciated by those in the art that many variable types of lumbar supports are known including many lumbar supports that are actuated by traction cables. Such traction cable actuated lumbar supports include, for example, arching pressure surfaces, such as are disclosed in U.S. Pat. Nos. 5,397,164 and 5,913,569, concave tensionable straps, such as disclosed in U.S. application Ser. No. 10/154,636, push paddles, such as are disclosed in U.S. application Ser. No. 09/798,657, and scissors type supports, such as are disclosed in U.S. application Ser. No. 10/315,320, all of which are incorporated by reference herein. Because of all of the referenced lumbar supports share the common feature of being actuated by traction that is applied with a traction cable, actuation of all these lumbar supports according to the automatic traction cable actuation described herein is considered to be within the scope of the present invention.  
         [0021]    In the depicted embodiment, lumbar support  20  is an array of flexible wires including horizontal wires  22  and vertical wires  24 . The depicted lumbar support wire array  20  is biased toward a substantially flat position. However, its flexibility allows it to be drawn into an arched or convex position having depth. This arched, convex position is achieved by the application of traction with traction cables.  
         [0022]    Traction cables are known in the industry. They are sometimes called “Bowden cables.” They include a sleeve or conduit with a cable or wire disposed within the sleeve and capable of sliding axially through it. As installed for use, an actuator at one end of the cable holds the sleeve end stationary while pulling the wire end out of the cable and away from the sleeve end. This achieves a corresponding traction or draw on the opposite end of the wire. The opposite end of the sleeve and wire are both connected to a lumbar support, or to a lumbar support combined with a connection to the seat frame. These connections are designed to move the lumbar support in to and out of arched, convex or otherwise lumbar supporting positions in response to the tractive force applied to the first end of the traction cable.  
         [0023]    In the depicted embodiment, tractive force is used to actuate the lumbar support via traction cables. Traction cable  30  is comprised of a sleeve (or “conduit”)  32  and a wire  34  sliding through the sleeve. The sleeve has an end  36  which is fixedly attached to the lumbar support at bracket  40 . Wire  34  extends beyond bracket  40 . Wire  34  has a hook  38  at its end by means of which the wire end  38  is attached to a hole or a notch in seat frame  10  that is preconfigured to receive wire end hook  38 . In the depicted embodiment, this hole or notch to which the wire end  38  is affixed is positioned forward of the bracket  40  and lumbar support  20 . As is best seen in FIG. 3, this forward positioning of the wire ends  38  creates a depth of space into which lumbar support  20  may be drawn when traction is applied to the traction cable. Schematic line  42  indicates the greatest extent of lumbar support depth achievable by the depicted embodiment. The difference between schematic line  42  in FIG. 3 and the flat position of lumbar support  20  depicted in FIG. 3 represents both the degree of lumbar support that will be automatically actuated by the apparatus of the present invention, and also represents the amount of space that will be saved upon automatic flattening of the lumbar support when the seat back is folded down into its flat position.  
         [0024]    As indicated above, vertical wires  24  and horizontal wires  22  are flexible. Of course seat frame  10  is inflexible. Accordingly, when traction is applied to traction cable  30  wire end  38  will not be able to move. Accordingly sleeve end  36  will move towards the point at which wire end  38  is attached to frame  10 . That is, it will move forward. Through bracket  40 , this will pull vertical wire  24  forward as well. In the depicted embodiment, this happens simultaneously on both lateral vertical wires. As is evident from FIG. 1, the attachment of brackets  40  and wire ends  38  is located at a position corresponding to the lumbar spine of the seat occupant. Accordingly a band of support will be created corresponding to the level of brackets  40  in the lumbar area. Wire array  20  is also supported at an upper end at mounts  44  and laterally at mounts  46 . These mounts are also flexible, but not being at a level corresponding to the brackets  40 , are not drawn forward into a lumbar supporting position. In an alternative embodiment, the entire wire array  20  may be replaced by an array having more rigid wires. For example vertical wires  24  could be completely rigid and horizontal wires  22  more stiff. In such a case, traction on the traction cables would draw the entire array forward creating a different sensation for a seat occupant which may be more desirable under some circumstances.  
         [0025]    Traction is applied at cable tension unit  50 . In the depicted embodiment, cable tension unit  50  rotates with the seat frame. Horizontal torsion rod  14  remains stationary, and does not rotate. In alternative embodiments also considered to be within the scope of the present invention, the torsion rod may turn with the seat back while the cable tension unit may remain stationary. Relative motion of the tension unit and torsion rod actuate the traction cable as follows. Cable tension unit  50  will have a hole or slot or channel narrowly dimensioned to allow passage therethrough of the traction cable wire  34 , but too narrow to allow passage of the traction cable sleeve  32 . Within the cable tension unit  50  traction cable wire  34  is attached to torsion rod  14 . This attachment may be by any of a wide variety of known means of mechanical attachment, including without limitation, pulleys, levers and the like. When the seat back is folded upwards into its up position, the tension unit and the cable sleeve end  52  mounts on it rotate away from the attachment of the traction cable  34  to the torsion rod  14 . The relative motion of cable tension unit  50  and torsion rod  14  will apply traction to draw the traction cable wire  34  out of and through the traction cable sleeve  32 . As explained above, this traction at the first end of the traction cable will engage and actuate the lumbar support  20  at the other end of the traction cable, causing it to be drawn by traction into its lumbar supporting position.  
         [0026]    Also depicted are bolsters  60 . Bolsters are paddles deployed on the sides of the seat for lateral support of the passenger. They are also actuated by traction in a known manner. Like the lumbar support, bolsters  60  have a non supporting flat position and a supporting extended position. The extended position has a greater depth, front to back, then the retracted or flat position. Actuation of the bolsters to move them into their extended position is achieved by connecting the traction cable  30  to the cable tension unit in the same manner as described above for actuation of the lumbar support  20 .  
         [0027]    The converse operation is folding down the seat back. Moving the seat back down will again move the cable tension unit  50  and the torsion rod  14  relative to each other. The cable tension unit is deployed such that this motion of the seat back downwards will move the cable sleeve end  52  and the attachment of the traction cable wire  34  closer to one another. This relaxes tension on the first end of the traction cable, which in turn reduces the distance between the second traction cable wire end  38  and a traction cable sleeve second end  36 . Accordingly, this relaxation of traction on the traction cable allows the lumbar support  20  and bolsters  60  to return to their untensioned, flat position. This return to the flat position is aided by the inherent spring or bias of the lumbar support wires  22  and  24  towards a flat position. It is also aided by the weight of the seat, weight of the cargo and force of the user pushing down on the back of the seat back.  
         [0028]    [0028]FIG. 5 is a cutaway detail of the cable tension unit  50 . The cable tension unit is fixedly attached to seat back frame in the depicted embodiment (not shown). Again, the torsion rod  14  could be fixedly attached to the seat back with the cable tension unit being fixedly attached to the seat bottom, as an alternative design. The present invention may be actuated by either component being attached to the seat back and the other component fixed to the bottom or otherwise fixed to the car frame, so long as the cable tension unit and torsion rod rotate relative to one another.  
         [0029]    Pulley  70  is attached to torsion rod  14  inside of the cable tension unit  50 . Pulley  70  is fixedly attached to the torsion rod  14  so that it does not move relative to the torsion rod  14 . Pulley  70  is designed to pick up and release traction cable wire  34 . Accordingly, pulley  70  has a circumferential channel  72  into which traction cable wire  34  may be taken up. Pulley  70  also has a seat  74  into which a bullet at the end of tension cable wire  34  may be inserted upon assembly. In operation, wire bullet seat  74  will hold the wire end in place as tension is applied. A slot  76  is fabricated into a wall of cable tension unit  50 . This slot is used in assembly to lead the traction cable wire  34  through the cable tension unit to where it can be seated on pulley  70 . Slot  76  also includes a key hole or a widening which forms another seat  78  for receiving the traction cable sleeve end  52 . Hence, keyhole seat  78  is wide enough to allow passage of the traction cable wire  34  therethrough, but not passage of the traction cable sleeve  32 .  
         [0030]    In operation, when the seat back frame is rotated up, cable tension unit  50  will also rotate up or in the direction indicated by arrow A in FIG. 5. In so doing, traction cable sleeve seat  78  and the traction cable sleeve end  52  seated within it will be moved away from where the traction cable wire  34  is anchored to the stationary pulley at  74 . This will of course have the effect of drawing the traction cable wire  34  through the traction cable sleeve  32 , and consequently applying traction to it. This traction will effect actuation of the lumbar support and, optionally, bolsters at the other end of the traction cable. Accordingly, when the seat back is up, the traction cable is tensioned and the lumbar support is out. When the seat back is folded down, or opposite to arrow A in FIG. 5, cable tension unit  50  is rotated in a direction that will move the traction cable sleeve end  52  closer to the traction cable wire end anchor  74 , allowing the tension on the wire to be reduced and allowing the wire to slide back into the sleeve  32 . Accordingly, released tension on the other end the traction cable will allow the lumbar support, and optionally bolsters, to flatten, thereby reducing the thickness of the seat back in its folded down position, increasing cargo space.  
         [0031]    It is considered to be within the scope of the present invention that various configurations of cable tension units may be used. For example, a traction cable sleeve mount seated in a portion of a seat back frame combined with a traction cable wire end bullet seat located in the frame of the seat bottom such that the sleeve end and wire end are separated when the seat is folded up. It is also contemplated that to be within the scope of the present invention that the automatic actuation upon folding of the present invention be combined with any of the variable lumbar support technologies incorporated by reference herein.  
         [0032]    In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained.  
         [0033]    The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.  
         [0034]    As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. For example, Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.