Patent Publication Number: US-6908153-B2

Title: Power lumbar support cable apparatus and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   None. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable. 
   FIELD OF THE INVENTION 
   This invention relates generally to an apparatus for reducing muscle fatigue and discomfort of a seated occupant and, more particularly, to an adjustable ergonomic support structure in a seat. The support structure in a seat may be adjusted to relieve muscle fatigue and discomfort. 
   BACKGROUND OF THE INVENTION 
   Individuals who remain seated for an extended period of time may develop symptoms of muscle fatigue and blood circulation problems. It is known that such muscle fatigue and circulation problems may be relieved, in part, by a lumbar support whose position is adjustable along a guide track. 
   Conventional adjustable lumbar support systems typically employ a mechanical adjusting means or a motor and gearbox assembly, commonly referred to as actuators, as an adjusting means. A four-way power lumbar support system may provide a level adjustment in a vertical direction and an arching adjustment of a flexible, resilient support element in a horizontal direction toward and away from a seat occupant. Such a system requires two separate actuators, that is, one for each adjustment direction. 
   Conventional variable lumbar support devices have generally included two traction cables for applying the force of the actuators to the lumbar support. Bowden cables are commonly used as traction cables for such devices. Lumbar supports employing Bowden type or other traction cable assemblies as part of a means for adjusting the lumbar support in a seat are known. Bowden or traction cables are coaxial mechanical devices wherein a wire slides axially through a sleeve or conduit. Traction cables have been found to be an efficient means for applying traction to moving parts of a lumbar support. 
   It is known to anchor a traction cable sleeve end to one part of the lumbar support device and to anchor the traction cable wire end to another part of the movable lumbar support device. When so anchored, drawing the traction cable wire through the traction cable sleeve causes the moving parts of the lumbar support device to travel from a relaxed, substantially flat and non-supporting position to a tensioned, supporting position such as a bowed arch. In the more expensive lumbar support systems, traction is applied via an electric motor, which acts on the end of the traction cable opposite the lumbar support device to draw the wire of a traction cable through the sleeve of the traction cable. For devices to be installed in more economical seats, mechanical actuators are used. 
   Prior art devices are known which provide lumbar supports that are slidable along a guide track. The support elements may be rigid or flexible. In some of these prior art devices, a traction cable is used to apply force to the support member for adjustment of the support member in one direction. Such an arrangement in conventional lumbar support systems has typically required the use of a spring to counteract the force of the traction cable, to bias the support member towards a rest position and to apply force to the support member in the return direction. Use of a spring to counteract the force of the traction cable is disadvantageous because overcoming the spring requires higher operating forces for the lumbar support system. 
   Such devices include several other drawbacks and limitations as well. Many of the commonly used adjustable lumbar support devices are composed of a relatively large number of parts. This is problematic because it renders these types of devices difficult to manufacture, package and assemble. Weight and expense are increased. Furthermore, these relatively complex conventional lumbar support devices are expensive to manufacture and may be unreliable and prone to breakdown. More powerful motors are required to overcome the forces of the springs, further increasing weight and expense. In mechanically actuated devices, complicated linkages become necessary to overcome the spring force. 
   Highly competitive markets for automobile seats and furniture place a premium on optimization of weight, cost and durability. There is a need in the industry for reducing the complication of assemblies, reducing packaging size, reducing cost and increasing durability. Accordingly, the need exists to provide an improved power lumbar support system that is cost-effective and light weight, yet still provides the quality of performance equal to that of conventional lumbar support systems. 
   SUMMARY OF THE INVENTION 
   The present invention provides such a power lumbar support system having improved packaging dimensions and lighter weight, while providing the comfort and lumbar support of conventional power lumbar support systems. The present invention&#39;s use of a novel cable assembly for the height adjustment of the lumbar support system reduces overall weight and expense. This novel cable assembly eliminates the need for certain spring and pulley elements and additional brackets for them that are used in conventional cable assemblies. Use of this cable assembly may also allow for the use of smaller diameter cables and a less expensive, lower power actuator. 
   A closed loop cable assembly or a two-cable assembly may be used in order to achieve these objectives. One traction cable end pulls the lumbar supporting element in a first direction, and another traction cable end, instead of a spring, pulls the support element in the opposite direction. The directions are usually vertical. 
   An additional cable actuates in and out motion. 
   The present invention is an ergonomic support device intended for use in automobile seats and furniture. This device includes a fixed mounting bracket having a first sleeve support, a second sleeve support and a slider guide; a traction cable having a wire disposed to slide axially through a first sleeve and second sleeve, with the first sleeve having a first sleeve end attached to the first sleeve support and a second sleeve end attached to an actuator operatively engaged with the wire, and the second sleeve having a first sleeve end attached to the second sleeve support and a second sleeve end attached to the actuator. The device further includes a slider that is attached to the wire. The slider is operatively engaged to the slider guide and adjusts an axial position of a flexible support element as it slides along the slider guide. 
   The present invention is an improvement over conventional power lumbar support systems in that it provides a system that is light weight, compact and requires fewer components. Additional features and advantages of the present invention, as well as the structure and operation of various preferred embodiments of the present invention, are described in detail below, with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a perspective view of the lumbar support system of the present invention. 
       FIG. 2  illustrates a rear view of the lumbar support system of the present invention. 
       FIG. 3  illustrates a front view of the lumbar support system of the present invention, without the basket attached. 
       FIG. 4  illustrates a rear view of the lumbar support system of the present invention, without the basket attached. 
       FIG. 5  illustrates a perspective view of the slider of the present invention. 
       FIG. 6  illustrates a cross-sectional bottom view of the slider of the present invention. 
       FIG. 7  illustrates front view of an embodiment of the present invention without the basket attached, having a two-cable assembly for height adjustment of the flexible support element. 
   

   DETAILED DESCRIPTION 
   Referring now to the drawings, there is depicted a lumbar support device  1  embodying the concepts of the present invention. The lumbar support device  1  of the present invention is generally identified in the drawings. In the preferred embodiment, the lumbar support device  1  may be used for providing lumbar support in the seat of an automobile. However, the present invention is not limited to use in automobile seats and may be used in any type of seat. 
     FIG. 1  shows a flexible support element  2  slidably connected to a guide wire  3 . The support element is sometimes known as a “basket” by those of skill in the art. The support element  2  is capable of adjustment in an in/out direction and an up/down direction relative to and along the guide wire  3 . The support element  2  may be made of any general material including plastic, metal or any combination thereof and is naturally biased towards a substantially flat shape. 
   The substantially parallel guide wire members  3 ′,  3 ′ have end stops  4  which prevent the support element  2  from sliding beyond the end stops  4 . In the embodiment depicted in  FIG. 1 , the guide wire  3  is comprised of a single wire member fabricated in a substantially U-shaped manner to provide two substantially parallel guide wire members  3 ′,  3 ′ that guide the support element  2  as it is adjusted in an up/down direction. The guide wire  3  is adaptable to mount the entire assembly in a seat frame (not shown). A mounting bracket  5  is connected to each of the guide wire members  3 ′,  3 ′ at a position between the opposite end stops  4  of the parallel guide wire members  3 ′,  3 ′. Any type of attachment device may be used to secure the mounting bracket  5  to the guide wire members  3 ′,  3 ′. For example, as shown in  FIG. 3 , the mounting bracket  5  may be attached to the parallel guide wire members  3 ′,  3 ′ via a plurality of anti-friction sleeve basket slots  6 . The mounting bracket  5  also includes a plurality of sleeve supports  7 ,  7 ′ for receiving and securing traction cable sleeves. 
   A slider  8  is slidably arranged on the mounting bracket  5 . The means by which the slider  8  is arranged on the mounting bracket  5  may vary. By way of example,  FIG. 5  shows the slider engaged in a slider guide slot  9  of the mounting bracket  5 , which allows for the sliding of the slider  8  along the slider guide slot  9  mounting bracket  5 . The slider guide may comprise a number of different structures designed to engage the slider  8  as it slides along the slider guide  9 , such as the slot shown in  FIG. 5 , or alternatively, a guide rail (not shown). 
   The depicted flexible support element  2  is capable of adjustment in a horizontal direction toward and away from a seat occupant. This adjusting in a horizontal direction is accomplished by virtue of a traction cable arrangement. The traction cable arrangement includes a first traction cable  10  comprised of a first wire  11  in a first sleeve  12 , wherein the first cable is attached to a first actuator  13 . The first actuator  13  may be any actuator used in conventional mechanical lumbar support systems for the purpose of providing arching directional adjustment of a flexible support element. The first wire  11  of the traction cable arrangement extends from the first sleeve  12  and is fixed at one end to the first actuator  13  and fixed at its other end to the support element  2 . The first wire  11  may be attached to the support element  2  in a number of different ways known in the art, including by way of a hook  14 , as shown in FIG.  1 . Traction drawing the first wire  11  into the first sleeve  12  will draw the bottom of support element  2  upwards, shortening the distance between the top and bottom ends of the support element  2 . This causes the support element  2  to bow outwards and create an arch to support the seat occupants&#39; lumbar spine. Reversing the first actuator  13  to extend the first wire  11  out of the first sleeve  12  will lengthen the distance between the top and bottom ends of the support element  2  and, along with the natural force that is created by the support element  2  as it returns to its natural, relaxed shape, will cause the support element  2  to move toward an unsupporting, substantially flat shape. 
   The first actuator  13  engages the first wire  11  in order to put traction on the first wire  11 . The rotating action of the first actuator  13  may be accomplished by a variety of means, including hand wheels or levers. The first actuator  13  may also be driven via an electric motor. The first actuator  13  may be mounted on the seat frame (not shown) or may advantageously be mounted to the bracket  5 , as shown in a preferred embodiment, seen in FIG.  1 . Attaching the first actuator  13  to the bracket  5  is advantageous for ease of packaging, shipping and installation of the lumbar support device  1 . 
   In the embodiment shown in  FIG. 1 , there is provided a second traction cable  15  that is a closed loop single cable (depicted) or, alternatively two separate, substantially opposing cables. The second traction cable  15  is comprised of a second wire  16  in an upper sleeve  17  and a lower sleeve  18 . The upper sleeve  17  is fixed at one end to a sleeve support  7  of the mounting bracket  5 , as shown in  FIG. 1 , and is fixed at its other end to a second actuator  19 . The sleeve support  7  is positioned to align sleeve  17  and wire  16  with the slider  8  and slider guide slot  9 . The lower sleeve  18  is fixed to sleeve support  7 ′ at the bottom end of the slider guide slot  9  and is fixed at its other end to the second actuator  19 . Like the first actuator  13 , the second actuator  19  may be mounted on the seat (not shown) or may advantageously be mounted to the bracket  5 , as shown in FIG.  1 . The end of the upper sleeve  17  and the end of the lower sleeve  18  may be fixed to the mounting bracket  5  a number of different ways, such as via sleeve supports  7 ,  7 ′, as shown in FIG.  1 . The second wire  16  is operably engaged with the second actuator  19  and is attached to the slider  8 . 
   Actuators known in the art, such as the depicted actuator  19 , may engage a central portion of a single wire such as wire  16  progressing through opposing Bowden cable sleeves such as the depicted sleeves  17  and  18 . In such a case, as in the depicted embodiment, the two ends of wire  16  are both attached to slider  8 . Alternatively, two separate traction cables with two separate sleeves and two separate wires may be attached to two separate actuators. In this case each cable would have a sleeve and a wire end attached to one actuator and an opposite end of each cable would have the opposite sleeve end attached to sleeve support  7  or  7 ′ and the opposite end of the wire would proceed from the sleeve end to be attached to the slider  8 . Hence slider  8  would be drawn in a first direction, for example upwards, by traction applied to it through one Bowden cable wire and the slider  8  would be drawn in a second direction, for example downwards, by traction on it by a second Bowden cable wire end. Accordingly, whether the slider  8  is acted upon by the two ends of a single wire, as depicted wire  16 , or whether it is acted upon by two separate wires, traction in a first direction will draw the slider upwards and the traction in the second direction would draw the slider downwards. 
   A yoke wire  20  has two engaging hooks  21 ,  21 , shown in  FIGS. 1 ,  2  and  3 , at one of its ends that engage two holes  22 ,  22  at the top end of the support element  2 . As shown in  FIGS. 4 and 5 , the slide  8  includes a third engaging hook  23 , which engages the yoke wire  20 . Yoke  20  serves to rigidly attach slider  8  with support surface  2 . Alternative attachments may be used. Accordingly, when slider  8  moves in either a first or second direction, the support element  2  will also move in the same first or second direction. Since the engagement of the first Bowden cable  10  which achieves the arching of the flexible support surface  2 , is through the slider  8 , the user selected degree of curvature of the flexible support element  2  will be preserved as the second Bowden cable(s)  15  moves the support element  2  upwards and downwards. Alternatively, a fixed (non-flexing) support may be used. 
   The device shown in  FIG. 1  operates in the following manner. The support element  2  is shown in a substantially flat, undeflected shape. As the first actuator  13  is activated to retract the first wire  11 , the distance between the top and bottom ends of the support element  2  decreases, resulting in the bowing of the support element  2  in an outward direction and thus providing additional lumbar support. The first actuator  13  may be activated by the occupant of a seat by use of a variety of equivalent activating means that are known in the art. Those skilled in the art will appreciate that that a variety of equivalent activating means may be used with the present invention without departing from the scope of the claims herein. 
   When the desired amount of lumbar support is achieved, the seat occupant may discontinue activation of the first actuator  13 . The tension between the first cable mount fixation to slider  8  and the first wire  11  mount  14  on support surface  2 , will maintain the degree of curvature selected by the user after the user disengages that actuator. Likewise, the first actuator  13  may be reversed to extend the first wire  11 , thus increasing the distance between the top and bottom ends of the support element  2 . As a result, the flexible support element  2  begins to relax in an inward direction, thereby flattening the support element  2 . 
   The system may also be operated to provide for adjustment of the support element  2  in a vertical direction. This is achieved by activating the second actuator  19  in a first direction, thereby resulting in the pulling of the second wire  16  in the first direction, for example, upwards. The linear movement of the second wire  16  is transferred to the slider  8  and causes the slider  8  to slide in an upward direction, along the slider guide  9  of the mounting bracket  5 . The slider  8 , in turn, transfers the force of the movement of the second wire  16  to the support element  2  through the fixed yoke wire  20 . This transferred force causes the support element  2  to move in an upward direction along the guide wire members  3 ′,  3 ′. 
   Because the slider  8  and flexible pressure surface  2  move in unison, the selected degree of arching of the support element  2  will be maintained during vertical movement of it by tension of actuator  19  through  16 . Adjustment of the support element  2  in a downward direction is likewise achieved by activating the second actuator  19  in a second direction to cause a second, opposing tractive force pulling the second wire  16  in a downward direction, again moving support element  2  through the linkage of Yoke  20 . 
   In another preferred embodiment shown in  FIG. 7 , the cable assembly for the adjustment of the support element  2  in the vertical direction includes two separate traction cables—an upper traction cable  24  and a lower traction cable  25 , shown in broken lines. This embodiment is similar to the other embodiment described herein, except that this embodiment employs two separate traction cables  24 ,  25  for level adjustment in a vertical direction. The upper traction cable  24  has one end operably coupled to an actuator  28  having a two-cable output and an opposite end operably coupled to the slider  8 . The upper traction cable  24  is comprised of an upper traction cable wire  26  in an upper sleeve  29 . The lower traction cable  25 , likewise, has one end operably coupled to the two-cable output actuator  28  and an opposite end operably coupled to the slider  8  and is comprised of a lower traction cable wire  27  in a lower sleeve  30 . Adjustment in a vertical direction is achieved by activation of the actuator  28 , which pulls either the upper traction cable wire  26  or the lower traction cable wire  27  to cause upward or, alternatively, downward travel. The linear movement of the upper traction cable wire  26  and the lower traction cable wire  27  is transferred to the slider and  8  causes the slider  8  to slide in either an upward or downward direction, along the slider guide  9  of the mounting bracket  5 . The slider  8 , in turn, transfers the force of the movement of the wires  26 ,  27  to the support element  2  through the fixed yoke wire  20 . This transferred force causes the support element  2  to move in an upward or downward direction along the guide wire members  3 ′,  3 ′. 
     FIGS. 5 and 6  are a close up and a cross section, respectively, illustrating a closer view of the slider  8  and its connections with the other elements of the present invention. Vertical traction wire  16  is mounted to a upper portion of slider  8  at mounts  30 . Any of a variety of mounts known in the art may be used. Typically, bullets on the ends of wire  16  would be seated in a recess molded or cut into the top of slider  8 . In the depicted embodiment the slider guide slot has been fabricated by cutting guide slot  9  from mounting bracket  5 , also producing the upturn edges of metal bracket  5  from where slot  9  has been cut. The upturn flanges  32  of mounting bracket  5  which define the edges of slot  9  slidingly engage slider  8  by means of their complementary cooperation with slider extensions  34 . Yoke  20  is fixed to the lower portion of slider  8  at yoke mount  23 . Underneath slider  8  and obscured by it in the perspective view of  FIG. 5 , is a sleeve support for first sleeve  10 . The end of first sleeve  10  is thereby attached to slider  8  so that arching tension may be applied to the support element. From the end of first cable sleeve  10  proceeds first cable wire  11  which proceeds to mount to support element  2  at hook  14  as shown previously in FIG.  1 . 
   Other objects, features and advantages will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited except as required by the scope of the appended claims.