Abstract:
A variable lumbar support has a support assembly mountable on a seat frame, a pressure element engaged with the support assembly to move in relation to it in a first direction and a second direction. The directions are substantially parallel and opposite and usually vertical. A first traction element engaged with the support assembly and the pressure element moves the pressure element in the first direction and a second traction element engaged with the support assembly and with the pressure element moves the pressure element in the second direction. At least one actuator engaged with the traction elements causes the movement.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     APPENDIX 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is in the field of adjustable ergonomic supports for seats, especially automobile seats. 
     2. Related Art 
     A variety of adjustable ergonomic supports for seating are known. These systems involve movement of an ergonomic support towards and away from the seat occupant in order to support various portions of the seat occupant&#39;s body. Many such ergonomic support devices, especially lumbar supports, also move vertically, so that apex of a lumbar supporting arch may be adjusted up and down so that the supports may be custom adjusted to particular individuals spine. 
     Such lumbar supports may be roughly divided into four classes. There is an arching basket type, see, e.g., U.S. Pat. No. 5,498,063; a push paddle type see, e.g., U.S. patent application Ser. No. 09/798,657; a tensioning strap type, see, e.g., U.S. Pat. No. 5,769,490; and pneumatic systems, see, e.g., U.S. Pat. No. 5,637,076, all incorporated by reference herein. All of these various types may be mounted on vertical slides so that they can be adjusted vertically. It is common for arching pressure surface type lumbar supports to be mounted on vertical guide rods. A pressure surface may be flexed or bowed outwards to provide a lumbar support, generally through the application of traction via a cable. The release of cable traction allows the natural bias of the pressure surface, usually stamped metal or molded plastic, to flatten it into a rest position, which action is augmented by the weight of the seat occupant. 
     There is not any natural bias or external force that helps the arching pressure surface type lumbar support to move in either vertical direction however. Prior art lumbar supports have achieved vertical movement of the arching pressure surface by biasing it towards a rest position, usually a bottom position, with springs. Vertical movement into a higher position has been achieved by attaching a single traction cable to the arching pressure surface. This mechanism requires a traction cable and an actuator for applying traction to the cable that are of a heavy enough gauge and great enough power can overcome the opposing tensioning force of the spring. 
     In the lumbar support field, as in auto parts in general, there is a continuing need for reducing costs, complexity and expense and also a continuing need for increasing durability, simplicity, compactness and ease of assembly. There is a need in the lumbar support arts for achieving vertical movement for a lumbar support in a manner that avoids the expense, complexity and weight of prior art single cable and spring apparatuses. 
     SUMMARY OF THE INVENTION 
     The present invention is a two cable system for vertical movement of a lumbar support. 
     In an arching pressure surface lumbar support with vertical adjustment capability, an arching pressure surface is mounted on vertical guide rails so that the entire pressure surface may slide vertically on the rails, either when the pressure surface is flat or bowed outwards to provide lumbar support. At one end of the pressure surface a traction cable is disposed to pull the pressure surface upwards. Another end of a traction cable is disposed to pull the pressure surface downwards. 
     In alternative embodiments, two separate traction cables may be used, or a single traction cable disposed in a loop fashion may be used. 
     Traction cables, such as the commonly used Bowden cable, are coaxial mechanical devices having a conduit or sleeve inside of which a wire is disposed to slide axially. In all embodiments, an end of a Bowden cable sleeve (or wire) is mounted to a fixed, non-moving support bracket and an end of the Bowden cable wire (or sleeve) is fixed to the arching pressure surface. An actuator at the other end of the Bowden cable applies traction, drawing the wire into the cable. At the first end of the Bowden cable the wire, now under traction, draws the pressure surface to which it is attached towards the fixed mounting of the Bowden cable sleeve end. The pressure surface slides vertically along the guide rails. The second Bowden cable sleeve end is also fixedly mounted to a bracket and a second Bowden cable wire end is also attached to the pressure surface and disposed to pull the pressure surface in the opposite vertical direction when tension is applied to the second Bowden cable wire. The fixed mounting of the Bowden cable sleeves may be on opposite vertical ends of the pressure surface. Alternatively, the fixed mounting of the Bowden cable sleeves may be on the same vertical end of the arching pressure surface, with the direction of one end of one of them redirected 180° by a pulley or other deflection apparatus fixedly mounted on the opposite end of the lumbar support. The two Bowden cable sleeve ends and wire ends may be opposite ends of a single Bowden cable, with an actuator remotely engaged thereto in order to pull it in either direction. Alternatively, two separate Bowden cables may be used. Two separate Bowden cables may be driven by a single actuator capable of bi-directional action, or by two separate actuators. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
     FIG. 1 illustrates a back view of a prior art four way lumbar support; 
     FIG. 2 illustrates a back view of a first embodiment of the two cable four way lumbar support of the present invention; 
     FIG. 3 illustrates a back view of another embodiment of the four way lumbar support of the present invention; and 
     FIG. 4 illustrates a side view of the second embodiment of two cable lumbar support of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the accompanying drawings in which like reference numbers indicate like elements, FIG. 1 depicts a prior art four way lumbar support from a back view. An arching pressure surface  2  is mounted on guide rails  4  at slide mounts  6 . The slide mounts  6  allow vertical or “up and down” travel of the entire arching pressure surface  2 . Up and down are two of the “four way” directions in which such a lumbar support may move. The other two of the four ways are “in and out.” That is, towards a seat occupant and away from the seat occupant. Movement towards the seat occupant is achieved by arching the flexible pressure surface  2 . It is achieved by moving the two pairs of slide guide rail mounts  6  towards one another. This movement is achieved by a traction cable drawing an upper portion and a lower portion of the arching pressure surface together. Accordingly, there is a traction cable  8  consisting of traction cable conduit  10  (also called a “sleeve” or “sheath”). A wire  12  is drawn coaxially through the conduit  10 , applying traction to the lumbar support. Traction is applied at the other end of the traction cable  8 , most commonly a Bowden cable, by an actuator (not shown). 
     In the depicted embodiment, the arching or “in and out” movement is achieved by traction that is applied to the arching pressure surface  2  by traction assembly  14 . There is a great variety of traction application assemblies, of which assembly  14  is only one. The feature common to all of them is that they apply traction to draw the upper portion and lower portion of the arching pressure surface  2  towards one another. 
     In the depicted embodiment, the mount  16  is hingedly attached to the arching pressure surface  2  at hinge  18 . Mount  16  has a Bowden cable conduit mount  20  and a Bowden cable wire mount  22 . At the opposite end portion of the arching pressure surface  2 , is a hinge  24 , and a deflection mount member  26 . The deflection mount member  26  has a deflector  28  which redirects the path of the Bowden cable wire  12  from the Bowden cable conduit mount  20  around the deflector  28  and back to the Bowden cable wire mount  22 . In operation, when an actuator (is not shown) applies forced to draw the Bowden cable wire  12  into Bowden cable conduit  10 , the mount  16  and mount  26  are drawn together, correspondingly drawing the ends of the arching pressure surface together, thereby causing the arch or bow that provides lumbar support. 
     The two cable system of the present invention is directed not towards the “in and out” movement but the “up and down” movement of the four way lumbar support. Accordingly, those of skill in the art will appreciate that arching traction application assembly  14  may be replaced by any other such assembly known in the art, or to be developed in the future. The two cable vertical motion system described below will work equally well with any such arching traction application assembly. 
     As with prior art systems, the vertical motion of the arching pressure surface may be effected regardless of the profile to which the arching pressure surface  2  has been bowed. 
     Guide rails  4  have mounted on them an upper bracket  30  and a lower bracket  32 . (Orientation is a design choice. Whether the brackets, mounts, and other elements of the present invention are installed as the “upper” or “lower” end is immaterial to the operation of the present invention.) The depiction of the prior art in FIG. 1 illustrates that springs  34  bias the pressure surface towards what is there shown as its lower position. The springs  34  are mounted at one end on bracket  32  and at their other end to the upper portion of arching pressure surface  2  with mounts  33 . In order to move the arching pressure surface from its lower most position, traction must be applied by a traction cable  36  in an upward direction. Accordingly, the vertical motion Bowden cable  36  has a conduit  38  with a wire  40  sliding coaxially through it. The conduit  38  is mounted on bracket  30  at mount  42 . Mount  42  allows wire  40  to proceed past or through it to where wire  40  is mounted on arching pressure surface  2  at mount  44 . An actuator (not shown) at the other end of cable  36  draws wire  40  into conduit  38 . The arching pressure surface  2  is pulled as a whole, upwards towards bracket  30 , against the force of springs  34 . 
     It is apparent that traction cable  36  and the actuator that applies traction to it must be of sufficient power and size to overcome the tensioning force of springs  34  in order to move the arching pressure surface  2  vertically and thereafter to maintain it in a selective position. 
     The two cable vertical motion system of the present invention allows elimination of the prior art springs  34 , and allows the use of smaller, lighter and less expensive components corresponding to cable  36  and the actuators for it. 
     FIG. 2 depicts a back view of a first embodiment of the two cable vertical motion system of the present invention. As with the prior art, an arching pressure surface  102  slides vertically on guide rails  104  via mounts  106 . 
     The novel two cable vertical motion system of the present invention uses one cable end to pull the arching pressure surface  2  upwards, and another cable end to pull it downwards, eliminating the need for springs. In the embodiment depicted in FIG. 2, bracket  130  has mounts for not one traction cable,  136 , but two, including also traction cable  110 . Traction cable  136  has a conduit  138  mounted at mount  142  on bracket  130 . Second traction cable  110  has a conduit  112  mounted on bracket  130  at mount  114 . 
     Another mount,  144  serves to fix Bowden cable wire ends to the arching pressure surface  102 . The present invention may be achieved by using either two Bowden cables with two wires having two ends, or, alternatively, by a single Bowden cable having a single wire arranged in a loop so that the two ends of the single wire may be applied for vertical movement of the arching pressure surface. FIG. 2 depicts an embodiment wherein a single Bowden traction cable wire is arranged in a loop having a first end  120 A and the second end  120 B, both of which are mounted to arching pressure surface  102  at mount  144 . Between its end regions  120 A and  120 B, the wire proceeds as a loop through the Bowden cable conduit  138  and through actuator  150 , powered by electric motor  152 . A variety of actuators are known in the art, including those that can apply traction in either direction to a continuous Bowden cable wire loop. After travelling through its engagement with actuator  150 , a single Bowden cable wire loop may proceed back through conduit  112 , around a deflection point or pulley  116  and back to a single mounting  144  to the arching pressure surface  120 . Alternatively, a separate mount may be used. 
     In operation, actuator  150  can pull the Bowden cable wire  120  A/B in a first direction to apply traction to mount  144  and raise the arching pressure surface  102 . The actuator  150  can also apply traction to Bowden cable wire  120  A/B in the opposite direction to apply vertical traction to arching pressure surface  102  at mount  144  to draw it downwards. 
     FIG. 3 depicts an alternative embodiment of the two cable vertical motion system of the present invention. Therein, arching pressure surface  202  rides on guide rails  204  at mounts  206 . In this embodiment, the upper traction cable  236  has a conduit  238  mounted to upper bracket  230  at mount  242 . Wire  220  proceeds from conduit  238  through or past mount  242  to mount  244  fixing wire  220  to arching pressure surface  202  at one end. In the depicted embodiment, actuator  250 , powered by motor  252  may draw wire  220  into conduit  238  in order to vertically raise the arching pressure surface  202 . 
     A second traction cable  210  is attached to the opposite end of the arching pressure surface  202 . In this depicted embodiment, the second wire  222 , which travels axially through conduit  212 , is not a continuous loop with the upper wire  220 , but rather an entirely separate wire. Out from conduit  212  and through or past mount  214 , which may be placed on transverse section of guide rails  204  or, alternatively, placed on a separate bracket (not shown), wire  222  proceeds to mount  224  where wire  222  is fixed to arching pressure surface  202 . An actuator  226 , powered by electric motor  228 , draws wire  222  into conduit  212 . This traction draws the arching pressure surface  202  downward. In operation, by coordinating the alternative operation of actuators  250  and  226  by known methods, two separate cables may raise and lower the arching pressure surface  202  without the presence of springs. 
     FIG. 4 is a side view of an arching pressure surface lumbar support incorporating the two cable system of the present invention. FIG. 4 shows the arching pressure surface  202  in a lower vertical position and, in phantom, in a raised position. The arching pressure surface  202  may be raised and lowered whether it is minimally arched or relatively flat, and when it is maximally arched. Actuators, not shown in FIG. 4, may be electrical, or, alternatively, may be manual. 
     In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained. 
     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. 
     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.