Abstract:
A scissors lumbar support includes a hinge axle and two arms each having a forward portion and a rearward portion. The forward portions are lumbar support pads. At least one of the rearward portions of the arms are adapted to operatively engage a force applicator. Each of the arms hinge around a hinge axle upon application of force by a force applicator. At least one of the rearward portions of the arms are mountable on a seat frame.

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 relates to ergonomic supports, especially lumbar supports, for seats, particularly for automobile seats.  
           [0005]    2. Related Art  
           [0006]    Modern seat designs commonly include lumbar supports for the comfort of the person sitting in the seat. In fact, it is becoming more common for seats to incorporate a variety of components for passenger comfort, including heating and cooling ducts and the like. The promulgation of components within the confines of a seat creates a need for smaller, more compact components. Saving space is also served by reducing the number of components required to provide ergonomic support.  
           [0007]    It is desirable in designing ergonomic controls for automobile seats to minimize the amount of manual effort a passenger needs to exert to move an ergonomic device such as a lumbar support through its full range of travel. A large number of turns required on a manual hand-crank or lever are undesirable. Generally speaking, prior art combinations of lumbar supports and actuators had a one-to-one ratio of actuator motion relative to lumbar support motion. For example, a traction cable would need to be pulled 10 millimeters in order to move a lumbar support attached to it 10 millimeters closer to a passenger. There is a need in the art for a lumbar support that increases the ratio of pressure surface travel to actuator movement.  
           [0008]    It is also desirable for ergonomic devices in automobile seats to be actuated by the lightest, and consequently least expensive, actuator components. Accordingly, it is desirable for a lumbar support configuration to reduce the load on actuators. There is a need for an ergonomic support whose configuration gives mechanical advantage to the actuator, so that lighter and less expensive actuator cables, gears, motors, etc. may be used.  
           [0009]    The most common current form of prior art lumbar support is a traction actuated arching basket such as those described in U.S. Pat. No. 5,397,164. This type of lumbar support uses traction to arch a flexible pressure surface towards the passenger by increasing the convexity of the bowed shape of the pressure surface. These pressure surfaces are naturally biased towards a flat position. The natural bias must be overcome by the traction device. Accordingly, there is an additional load that must be overcome by the actuator. In addition to the load created by the weight of the passenger, these prior art lumbar devices have to overcome the load of flexing the pressure surface, and overcome the friction inherent in sliding the moving ends of such arching lumbar supports along their stationary mounts. There is a need in the art for a lumbar support configuration that eliminates unnecessary loads.  
           [0010]    Some lumbar supports move up and down in the seat to raise and lower the point of support. Such supports must overcome the friction of moving along the seat cushions. There is a need to eliminate such friction.  
           [0011]    Another disadvantage of arching lumbar supports is that as the pressure surface extends farther towards the passenger, the surface area contacting the passenger shrinks, which is less comfortable. The pressure surface also becomes more rigid at its furthest extension, which is also uncomfortable. There is a need for a lumbar support that retains its full effective surface area and flexibility when extended.  
           [0012]    Furthermore, in the particular art of supporting the lumbar spine, there is a need for spinal relief. That is, the bony vertebrae of the spine become uncomfortable if direct pressure is applied to them by a lumbar support pressure surface. It is preferable to apply lumbar supporting pressure bilaterally adjacent to the spinal column, while maintaining a vertical recess or channel to accommodate the vertebrae.  
           [0013]    As with all auto parts, there is a constant need in seat assembly procedures to increase the economy, speed and efficiency of component assembly and shipping. There is a further need in seat design for strong, economical, compact components.  
           [0014]    Producing fewer parts serves these needs. Nevertheless, the device must remain strong and stay robust through many cycles of use.  
         SUMMARY OF THE INVENTION  
         [0015]    The present invention is an ergonomic support, particularly as used for a lumbar support, that acts in a scissors motion. Bilateral lumbar supporting pads have a hinge between them. Each pad has a lever arm that extension to the rear of the hinge, away from the seat occupant. These extending arms are attached to any of a variety of force applying means, for example, a Bowden cable. Traction on the Bowden cable draws the lever arms together, which causes a scissors action through the hinge, causing the forward lumbar supporting pads to extend towards the seat occupant.  
           [0016]    The rearward extensions also provide a mount site for installation in a seat frame.  
           [0017]    The present invention supports the lumbar spine with pressure surfaces that are generally vertical and located bilaterally adjacent to the vertebra of the spine. The centrally located, vertical hinge creates a channel for relief of pressure on the spinal vertebrae.  
           [0018]    The present invention makes the combination of components within a seat more compact, especially with regard to eliminating the bulk and number of components required. It uses a relatively small number of moving parts which are simple in design and movement. The present invention streamlines the manufacture, assembly, packaging and shipping of the device and of seats incorporating the device, lowers production costs and increases the durability and useable life of the device and seats incorporating it. The scissors ergonomic support may be mounted in any of a variety of seat frames and suspension systems.  
           [0019]    The scissors lumbar support of the present invention creates an increased ratio of pressure surface travel towards a passenger in relation to the travel required of an actuator linkage, such as a Bowden cable. The pressure surfaces of the scissors lumbar support move out relative to the pivot upon actuation. Also, the pivot itself moves out an additional amount relative to the seat frame because the scissors lumbar support is mounted at the rearward lever arm extensions. A greater than 1-to-1 ratio of pressure surface travel to actuator linkage travel is thereby achieved. Depending upon the length of lever arm extensions, the travel ratio may exceed 2 to 1.  
           [0020]    The scissors lumbar support inherently lends mechanical advantage to an actuator. The action of lever arm extensions behind the hinge upon the pressure surfaces ahead of the hinge works as any lever, and multiplies the force applied to the pressure surface by the actuator linked to the rearward lever arm extensions. Accordingly, lighter and less expensive actuators and actuator linkage components, such as Bowden cables, may be used. Moreover, there is substantially less friction in the scissors lumbar support of the present invention than with prior art arching pressure surfaces.  
           [0021]    The scissors lumbar support retains the flexibility of its pressure surfaces in its extended position. This is more comfortable for the passenger. It also maintains the full surface area that contacts the passenger.  
           [0022]    Another embodiment of the scissors lumbar support is mounted to rock around a horizontal axis in order to raise or lower the apex of support. By rocking instead of sliding, friction between the pressure surface and seat cushions is eliminated.  
           [0023]    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  
       [0024]    [0024]FIG. 1 is a front, perspective view of the scissors lumbar support in a retracted position  
         [0025]    [0025]FIG. 2 is a front, perspective view of the lumbar support in an extended position.  
         [0026]    [0026]FIG. 3 is a back perspective view of the lumbar support in a retracted position.  
         [0027]    [0027]FIG. 4 is a back perspective view of the lumbar support device in an extended position.  
         [0028]    [0028]FIG. 5 is a schematic top view of the scissors lumbar support in a retracted position.  
         [0029]    [0029]FIG. 6 is a schematic top view of the scissors lumbar support in an extended position.  
         [0030]    [0030]FIG. 7 is a front, perspective view of an alternative embodiment of the scissors lumbar support in an extended position.  
         [0031]    [0031]FIG. 8 is a back perspective view of an alternative embodiment of the lumbar support in an extended position.  
         [0032]    [0032]FIG. 9 is a back perspective view of an alternative embodiment of the lumbar support device in a retracted position.  
         [0033]    [0033]FIGS. 10A, 10B,  10 C,  10 D,  10 E and  10 F illustrate the rocking movement of the scissors lumbar support mounted in its second embodiment.  
         [0034]    [0034]FIG. 11A is a schematic illustration of the flexion of the scissors lumbar support.  
         [0035]    [0035]FIG. 11B is a schematic illustration of the flexion of a prior art lumbar support.  
         [0036]    [0036]FIG. 12A is a schematic illustration of the pressure surface area maintenance of the scissors lumbar support.  
         [0037]    [0037]FIG. 12B is a schematic illustration of the pressure surface maintenance of prior art lumbar supports.  
         [0038]    [0038]FIG. 13 is a back perspective view of an embodiment of the scissors lumbar support in a two way manual configuration.  
         [0039]    [0039]FIG. 14 is a back perspective view of an alternative embodiment of the scissors lumbar support in a two way power configuration, in an extended position.  
         [0040]    [0040]FIG. 15 is a back perspective view of an alternative embodiment of the scissors lumbar support in a four way power configuration.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0041]    Referring to the accompanying drawings in which like reference numbers indicate like elements, FIGS. 1 and 2 are front views of the first embodiment of the scissors lumbar support of the present invention. FIGS. 3 and 4 are back views of the first embodiment and FIGS. 5 and 6 are top views of the first embodiment.  
         [0042]    Referring now to FIGS. 1 and 2, the present invention is comprised of two hinging arms,  10  and  12 , connected at a vertical hinge,  8 . These arms are preferably molded plastic but may be metal. They are deployed in a left handed and right handed fashion. They may be manufactured in left and right handed versions, but preferably are manufactured to be symmetrical. In assembly, in order to create a bilateral hinge support from symmetrical arms, one of the arms is simply inverted to create the mirror image of the other.  
         [0043]    Each arm has three portions. A forward extending aspect,  14  and  16 , is the lumbar supporting pressure surface or pad. Although the configuration of the forward extending support surface may vary, the lumbar supporting pad,  14  and  16  are preferably curved around a vertical axis and convex towards the seat occupant. It is preferably tapered from its medial to its distal side, and may optionally have ribs  18 , or holes to promote flexibility.  
         [0044]    The scissors lumbar support will hinge at the medial portions of the arms. In this medial portion of each arm, are at least one, and preferably 2 or more hinge knuckles  22  having vertical through holes. The through holes receive insertion during assembly of a hinge pin (not shown). Caps, bends or other pin end stops hold the components in their assembled configuration.  
         [0045]    Mounting wires  24  attach the lumbar support to a seat frame  26 .  
         [0046]    [0046]FIG. 1 shows the lumbar support in its flat, retracted, non-supporting position. FIG. 2 shows the lumbar support in its extended position. It may be placed in intermediate positions.  
         [0047]    [0047]FIGS. 3 and 4 are back views which depict the flat and the extended positions, respectively. The rearward portion of each arm is one or more lever extensions,  28  and  30 . On each lever arm extension  28 ,  30 , is a mount, preferably at the distal end. In the depicted embodiment, the mount of the center lever extensions is simply a slot or notch  32 , dimensioned to receive a Bowden cable wire. Bowden cable  34  has a sleeve  36  and a wire  38  slidingly disposed through the central axis of the Bowden cable. In assembly, a sleeve cap  40  is placed adjacent to one slot  32  towards the outside of lever arm extension  28  or  30 . Wire  38  is slid into place into the slot  32  and extended to the opposing slot  32  on the other extending lever arm,  30  or  28 , where it is also slid into place in the other slot  32 . Wire  38  has an arresting end cap  42  holding it in its place in slot  32 . The other end of Bowden cable  34  has an actuator  44  for tractively drawing wire  38  into sleeve  36 .  
         [0048]    In the depicted embodiment, the mounts of the upper and lower lever extensions are the slots or notches  33  dimensioned to receive the mounting wires  24 . Ridges  20  may be included to retain strength.  
         [0049]    In operation, traction on wire  38  draws wire end cap  42  and lever arm extension  28  or  30  towards Bowden cable sleeve cap  40  and the other lever arm extension  30  or  28 . This creates a scissors action through the hinge  8 , causing the lumbar support pads,  14  and  16 , to extend outward from the plane of the seat, towards the seat occupant, thereby applying lumbar supporting pressure. All of the hinging motion of the arms is forward, because rearward extension is arrested by the mounting wires  24  along which the rearward lever arm extensions  28  and  30  slide on mounts  33 .  
         [0050]    [0050]FIGS. 5 and 6 are top views of the scissors lumbar support in its flat and extended positions, respectively. Rearward lever arm extensions  28  and  30  can be seen in alignment with the mounting wires  24  to which they are attached at mounts  33  and along which they slide upon extension. A hinge pin  46  is depicted joining the two halves of the scissors lumbar support at hinge  8  by its insertion through the vertical through holes of the alternating knuckles  18 . Support surfaces  14  and  16  face the seat occupant, who would be towards the top of the page in FIGS. 5 and 6.  
         [0051]    [0051]FIG. 6 shows all of the same components with the scissors lumbar support in its extended position. Supports surfaces  14  and  16  appear somewhat flattened, as they would be in use. Additionally, Bowden cable wire  38  is visible. FIG. 6 also depicts one of the advantages of the present invention, which is this spinal relief area,  48 .  
         [0052]    Those who are skilled in the ergonomic arts appreciate that the particular shape of the human anatomy must be accommodated for ergonomic support devices to make the seat occupant comfortable. For lumbar supports, this necessity includes incorporating a gap or indentation in any lumbar support to avoid uncomfortable point pressure on the vertebral process of the spine. Prior art lumbar supports created such a spinal relief gap by machining or molding an indentation into the lumbar support pressure surface. As is evident from FIG. 6, the hinged extension action of the scissors lumbar support automatically creates such an advantageous gap  48  for spinal relief when it is moved from its flat position, as shown in FIG. 5, to its extended position, as shown in FIG. 6.  
         [0053]    Comparison of FIGS. 5 and 6 illustrates further advantages of the scissors lumbar support. It is appreciated by those with skill in the art that it is desirable to maximize the outward travel of the lumbar support pressure surface relative to the travel of the Bowden cable wire. This is particularly true for manual actuators which require a user to turn a crank on a manual actuator in order to cause the Bowden cable wire to travel relative to the Bowden cable sleeve, which in turn causes the lumbar support pressure surface to travel towards the seat occupant. It is desirable that the full range of pressure surface travel be achieved with the minimum number of manual actuator turns, for user convenience. Therefore, if the ratio of pressure surface outward travel to manually actuated Bowden cable travel is greater than 1 to 1, it is more convenient for the user.  
         [0054]    The scissors lumbar support of the present invention has two mechanisms by which outward travel of the pressure surface is achieved. First, the rotation of the arms  10  and  12  around the hinge  8  extends the pressure surfaces  14  and  16  towards the seat occupant. If the scissors lumbar support was mounted at its hinge, this would be the only mechanism for pressure surface extension. The scissors lumbar support may be alternatively mounted at its hinge, but the preferred embodiment of the scissors lumbar support is mounted not at its hinge, but rather at the ends of the rearward extension arms  28  and  30 . When the tension of the Bowden cable wire  38  draws these 2 arms closer together, they slide along the mounting wire  24 . This action moves the hinge itself outwards towards the seat occupant. This additional extension mechanism creates a greater than 1 to 1 ratio of outward pressure surface travel to Bowden cable travel. Accordingly, the full extension of the scissors lumbar support pressure surface can be achieved with fewer turns of a manual actuator, making the scissors lumbar support more convenient for a seat occupant&#39;s use than prior art lumbar supports.  
         [0055]    Another advantage of the scissors lumbar support over the prior art is the flexibility of the pressure surfaces  16  and  14 . Distal to the spinal relief area  48  are the contact portions  50  of each pressure surface  14  and  16  that contact the paravertebral region of the seat occupant&#39;s lumbar spine. Distal to the pressure surface contact zones  50  are the flex zones  52  which are more flexible than the contact zones  50  of the pressure surfaces. This gradual progression from lesser to greater flexibility is more comfortable for the seat occupant. Greater stiffness and strength may be promoted in the contact zones  50  with reinforcing ridges  20 . Greater flexibility in the flex zones  52  may be promoted by designing the flex zone with holes, or ribs.  
         [0056]    [0056]FIG. 7 is a front view of a scissors lumbar support incorporating an additional feature enabling the lumbar support to create a high or low lumbar supporting effect. This embodiment of the scissors lumbar support can selectively urge either the lower half or the upper half of the pressure surfaces  14  and  16  towards the seat occupant. This is done by rocking the entire lumbar support assembly up or down.  
         [0057]    [0057]FIGS. 8 and 9, the back view of this embodiment, shows the mechanism for rocking the assembly. In order to rock the bottom portion or the top portion of the pressure surfaces  114  and  116  towards the seat occupant, the assembly pivots on a horizontal rod  124  at or near the vertical midpoint of the lumbar support. Accordingly, there is only one mounting wire,  124 . Mounting wire  124  has a central offset  125 . The upper and lower lever arm extensions  128  and  130  are mounted on a frame wire  160 . Lever arm extensions  128  and  130  slide laterally along frame wire  160  during extension.  
         [0058]    The frame wire  160  is in turn mounted on bracket  162 . Bracket  162  has pivot mounts  164 , by which it is connected to mounting wire  124  such that the frame  162  can pivot on the mounting wire  124 .  
         [0059]    The embodiment depicted in FIGS.  7  to  9  extends the scissors in the manner described above, but with a power actuator  154 .  
         [0060]    The rocking motion of the assembly is actuated by a second power actuator  166  in the depicted embodiment, although a manual actuator may be used. Actuator  166  is connected to Bowden cables  168  and  170  such that tightening of one Bowden cable loosens the other. The Bowden cable sleeves are mounted to frame  162  at sleeve end mounts  172  and  174 . The Bowden cable wires are mounted with wire hooks  176  and  178 . The wires are hooked to the off-set  125  of mounting wire  124 . Offset  125  creates a depth-wise diagonal path for the Bowden cable wire. Accordingly, when one of the Bowden cables is tightened, one end of the frame is drawn closer to the off-set  125 , drawing that end of the frame  162  towards the rear of the seat. Since the bracket  162  frame wire  160  and lumbar supporting panels  110  and  112  move as a unit, rearward traction on one end of bracket  162  will bias the opposite end of the lumbar support pressure surfaces  114  and  116  towards the seat occupant.  
         [0061]    For example, if lower Bowden cable  170  is tightened, lower Bowden cable sleeve mount  174  is drawn closer to off-set  125  in mounting wire  124 . This motion will urge the upper most portion  180  of the lumbar support pressure support surfaces  124  and  116  towards the seat occupant. Tightening of the opposite Bowden cable  168  will likewise urge the lower-most portion  182  of the lumbar support pressure surfaces towards the seat occupant.  
         [0062]    The rotating operation of the assembly is illustrated in FIGS. 10A, 10B,  10 C,  10 D,  10 E and  10 F. In FIGS. 10A, 10B and  10 C the lumbar support is in its fully extended position. In FIGS. 10D, 10E and  10 F the lumbar support is in its fully retracted position. In either position or in any intermediate position the assembly can rock to create a high apex, a low apex or a flatter, intermediate position. In FIG. 10A the assembly has been fully extended and rocked to its low apex position. In FIG. 10B the assembly has been fully extended and remains in its intermediate position. In FIG. 10C the assembly has been fully extended and rocked to its high apex position. In FIG. 10D the assembly has been fully retracted and rocked to its low apex position. In FIG. 10E the assembly has been fully retracted and remains in its intermediate position. In FIG. 10F the assembly has been fully retracted and rocked to its high apex position.  
         [0063]    Schematic illustrations  11 A and  11 B illustrate the maintenance of flexion zones upon extension that is achieved by the scissors lumbar support. FIG. 11A shows that the entire support pad surface is advanced towards the seat occupant upon actuation and extension of the lumbar support. Above and below the apex zone  202  are flexion zones  204 . Because the mechanism of the scissors lumbar support does not require the application of force to the upper and lower ends of the pressure surface, the flexion zones  204  are advanced towards the seat occupant co-extensively with the apex  202 . Empirical studies have demonstrated that such flexion zones increase passenger comfort. By contrast, FIG. 11B illustrates the prior art arching basket-type lumbar support in operation. With the prior art lumbar support, the flexion zones  214  are encapsulated by the tensioning mechanism of the lumbar support, and unable to advance towards the seat occupant as the apex zone  212  advances. Accordingly, there is a loss of flexion zones. Also, the apex zone  212  on prior art lumbar supports becomes increasingly rigid upon extension, thereby further diminishing the comfort of the passenger.  
         [0064]    [0064]FIGS. 12A and 12B illustrate the advantageous maintenance of full pressure zone height that is achieved with the scissors lumbar support. Because the entire pressure surface is advanced towards the passenger upon extension of the scissors lumbar support, the push zone  220  does not lose any height as it is extended further towards the passenger. By contrast, FIG. 13B illustrates that the push zone  230  of prior art lumbar supports decreases vertically with further advancement of the lumbar support. Accordingly, the scissors lumbar support is more comfortable than the prior art supports.  
         [0065]    [0065]FIGS. 13, 14 and  15  show another embodiment of the scissors lumbar support in three different configurations. In this alternative embodiment, the shape of the lumbar supporting panels  310  and  312  has been changed. As is evident from these figures when compared to the earlier figures a broad variety of shapes are available for use as lumbar supporting panels without departing from the scope of the present invention. In the currently depicted embodiment the pressure surfaces  314  and  316  normally function in the manner previously described, as does hinge  308 .  
         [0066]    In the alternative embodiment depicted in  13 ,  14  and  15 , the lever arm extensions  328  and  330  are unified to promote strength. FIG. 13, a single, wide extension  328  supports both the Bowden cable sleeve mount  340  and two sliding mounts  333  for mounting the assembly on two guide wires  324 . The complementary lever arm extension  330  is a U-shaped member having a single vertical web joining two upper and lower extension so that it too supports not only sliding mounts  333  for movement along guide rails  324 , but also the Bowden cable wire mount  42 . The sleeve mount  340  and wire mount  342  may be interchanged, as depicted in FIG. 14.  
         [0067]    In FIG. 14 the same alternative embodiment is used in a configuration employing a power actuator  354  to cause the scissors action of the lumbar support. In FIG. 15 the same alternative embodiment is employed in a power configuration depicted in FIG. 8 wherein the unit may be tilted on the horizontal axis of guide rail  324  to create either a higher or lower lumbar support. In both FIGS. 14 and 15, the engagement and operation of the actuators and Bowden cable with the scissors lumbar support is as previously described.  
         [0068]    In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained.  
         [0069]    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 and various embodiments and with various modifications as are suited to the particular use contemplated.  
         [0070]    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. 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.