Abstract:
A braking actuator for continuously positionable ergonomic support has a continuously positionable ergonomic support connected by a Bowden cable to the actuator. The actuator has a housing with pin slots, friction surfaces and an oval mount for a disk axle. A disk has frictional surfaces, holes with pin load edges, a Bowden cable wire seat that holds the Bowden cable end and an axle that mounts in the oval mount in the housing. The friction surfaces of the disk and housing engage to brake the actuator and the ergonomic support. A lever having pins is disposed on said housing such that said pins extend through the pin slots to operatively engage the holes in the disk such that the friction surfaces can be disengaged and said disk rotated. Turning the lever disengages the friction surfaces to actuate movement of said ergonomic support. Releasing said lever engages said frictional surfaces such that movement of said ergonomic support is braked at a selected position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    None.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         APPENDIX  
         [0003]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0004]    1. Field of the Invention  
           [0005]    The invention is an actuator used to move and hold ergonomic supports for seats and chairs.  
           [0006]    2. Related Art  
           [0007]    Automobile and furniture seats frequently include ergonomic supports, such as lumbar supports. There are several types of lumbar supports, including arching pressure surfaces, See, e.g. U.S. Pat. No. 5,397,164, push paddle type lumbar supports, See, e.g. U.S. Pat. No. 4,295,681, and strap type supports, See, e.g. U.S. patent application Ser. No. 09/485,738. The common features shared by all these varieties of ergonomic support include being continuously positionable and being operated by an actuator installed on an exterior surface of the seat so that it can be controlled by person sitting in the seat. Many of these actuators are manual, mechanical devices.  
           [0008]    Continuously positionable ergonomic supports have a range of motion. The support device can be moved through its range of motion by the actuator in continuous, stepless fashion. The actuators for these supports include a variety of clutches or brakes so that any position in the range of motion that the user finds comfortable may be held in place by the actuator.  
           [0009]    The actuators move and hold the ergonomic supports by means of traction cables in the majority of cases. The most common traction cable is a Bowden cable. A Bowden cable is a flexible conduit or sleeve. A wire is disposed inside the sleeve and is axially slideable through it. At one end of the Bowden cable, the sleeve end is mounted on one part of the ergonomic support and the wire end is mounted on another part of the ergonomic support. Traction drawing the wire through the sleeve moves the ergonomic support and the release of tension on the Bowden cable wire allows the ergonomic support to return through the same range of motion in reverse.  
           [0010]    At the other end of the Bowden cable, an actuator must be able to pull the Bowden cable wire through the Bowden cable sleeve in order to move the ergonomic support through its range of motion. The actuator must firther be able to hold ergonomic support in the users selected position against the traction exerted on the Bowden cable wire by the pressure of the user sitting on it.  
           [0011]    Prior art actuators achieve these design goals through mechanisms that were complex, and therefore expensive, See, for example, U.S. Pat. No. 5,794,479, U.S. Patent No. 6,178,838, U.S. Patent No. 6,230,867 B1. The use of such overrunning clutches, ratchets, bearings, and eccentric rings involve a large number of parts, increasing the expense of the actuator both in terms of the number of parts required and their assembly. Moreover, such devices do not wear well and tend to break or slip after a number of use cycles shorter than the predicted lifetime of the seat in which they are installed. There is a need in the industry for an ergonomic support actuator that reduces cost, decreases complexity, and increases durability.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention is a braking ergonomic support actuator. It is manual. The user turns a lever in order to put traction on a Bowden cable to actuate a continuously positionable ergonomic support device.  
           [0013]    The braking actuator is comprised of a housing, a disk and a lever having pins. A Bowden cable sleeve is mounted on the exterior of the housing. The Bowden cable wire is mounted on the disk which is disposed to rotate within the housing. The lever has pins that extend through slots in the housing and engage the disk to put actuating pressure on it.  
           [0014]    The housing and disk have complementary friction surfaces. The Bowden cable wire is mounted on the disk so that rotation of the disk in a first direction exerts tractive force on the wire and rotation of disk in the opposite direction releases tension on the wire. This force is imparted to the disk by the user turning the lever, causing the pins to push the disk. The engagement of the friction surfaces on the disk with the friction surfaces on the housing are sufficient to brake the rotation of the disk against the return pressure on the wire exerted by the pressure of the seat occupant on the ergonomic support surface. The braking friction surfaces are given mechanical advantage over the force on the Bowden cable wire by being placed at a greater radial distance from the axis of the disk than the seat of the Bowden cable wire.  
           [0015]    In order that the ergonomic support surface may be moved from where it is held in a selected position, the actuator must be able to release the brake. This is achieved by raising the disk out of its frictional engagement with the housing. In one preferred embodiment, the edge of the disk is a wedge. The edges of the wedge are frictional surfaces. The pressure of the ergonomic support on the Bowden cable wire forces the wedge into the corresponding wedge seat. The wedge seat is comprised of the frictional surfaces of the housing. In order to release the braking effect of this frictional engagement, the lever must move the disk upwards out of the wedge seat, against the force of the Bowden cable wire. This raising motion is immediately followed by a rotating force, which is also applied to the disk by the lever. A first direction of this rotating force will exert extra traction on the Bowden cable wire moving the ergonomic support through its range of motion in a first direction. In the other direction, the lever turns the disk to release tension upon the Bowden cable wire, returning the ergonomic support through its range of motion.  
           [0016]    The lever has pins fixedly attached to it. These pins are parallel to the axis of the disk and extend through slots in the housing. Inside the housing, the pins engage holes in the disk. The edges of these holes comprise loading surfaces against which the pins push to first release the brake and secondly move the disk in one rotational direction or the other. In one preferred embodiment, there are two pins, two pin slots in the housing and two loading surface holes to receive the pins in the disk. In one preferred embodiment, the loading surface holes are oblong and nonparallel, in order that the disk may quickly respond to pressure on the pins.  
           [0017]    The disk has an axle which is mounted in an axle housing seat. In order to allow the slight but necessary upwards movement of the disk out of engagement with the frictional surfaces of the housing, thereby releasing the brake, the axial housing mount for the disk axle is oval shaped. This shape gives the disk axle room to move upwards, and thereby to move the disk up and out of braking engagement with the housing.  
       
    
    
       [0018]    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  
       [0019]    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:  
         [0020]    [0020]FIG. 1 depicts a continuously positionable ergonomic support device connected by a Bowden cable to an actuator;  
         [0021]    [0021]FIG. 2 depicts a braking actuator assembled;  
         [0022]    [0022]FIG. 3 illustrates a top view of the braking actuator with the top housing removed;  
         [0023]    [0023]FIG. 4 illustrates a top view of the braking actuator disk;  
         [0024]    [0024]FIG. 5 illustrates a side view of the braking actuator disk;  
         [0025]    [0025]FIG. 6 is a schematic side view close up of the interaction of the braking actuator disk with the braking actuator housing friction surface;  
         [0026]    [0026]FIG. 7 is a schematic top view of the braking actuator disk&#39;s interaction with the Bowden cable wire and the housing friction surface;  
         [0027]    [0027]FIG. 8 is a perspective view of the braking actuator with the housing top and disk removed; and  
         [0028]    [0028]FIG. 9 is a schematic view of the disk depicting its interaction with the lever pins.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]    Referring to the accompanying drawings in which like reference numbers indicate like elements, FIG. 1 illustrates a continuously positionable lumbar support and its relationship to a Bowden cable  4  and actuator  6 . The pressure surface  2  is mounted to guide rails  8  and at least one portion of the arching pressure surface  2  slides up and down along guide rails  8 . Bowden cable  4  includes a Bowden cable wire  10 . A Bowden cable sleeve  16  is mounted to one end of the arching pressure surface  2  at a sleeve mount  12 . The Bowden cable wire  10 , which slides axially through the Bowden cable sleeve  16 , is mounted to another portion of the arching pressure surface  2 , at Bowden cable wire mount  14 . When actuator  6  is engaged, it puts traction on the Bowden cable wire  10  drawing it axially into Bowden cable sleeve  16 . This is turn puts tractive force on the arching pressure surface  2  at the Bowden cable wire mount  14  drawing it and the Bowden cable sleeve mount  12  closer together. This causes the arching pressure  2  to bow or arch outwards towards a seat occupant as one or both portions of the arching pressure surface  2  slide along guide rails  8 .  
         [0030]    Generally, most ergonomic supports have a natural bias towards a flat position. This bias is contributed to by forces including the pressure of the seat occupant on the lumbar support, a natural bias of the arching pressure surface (or analogous members in other systems) towards a flat position, and, alternatively, by springs (not shown). Accordingly, when in use in any position besides the flat position, there will be a force exerted on the Bowden cable wire  10  pulling it outwards from the Bowden cable sleeve  16 . The sliding motion of the arching pressure surface  2  is continuous, without steps, so that a user may select any position along a continuous range of positions through the device&#39;s entire range of motion.  
         [0031]    [0031]FIG. 2 depicts the assembled braking actuator  6 . Lever  20  is rotatably engaged with housing top  22  by any of a variety of methods, for example, annular bosses and detents (not shown). Also visible are Bowden cable sleeve  16  and, Bowden cable sleeve mount  24 . In the center of housing top  22  is an oval shaped disc axle mount  26 .  
         [0032]    [0032]FIG. 3 is a top view of the braking actuator with the top section of housing  22  removed.  
         [0033]    Visible are housing bottom half  30 , disk  40  and the small gap between them  32 . Lever  20  is fixedly attached (preferably molded as a single piece), to lever mounting ring  28 , which circumscribes housing bottom  30  and is in rotatable engagement with it. Bowden cable sleeve  16  is attached to housing bottom  30  at Bowden cable mount  24 . Bowden cable wire  10  extends from sleeve  16  into the space provided for it within the actuator housing between housing top  22  and housing bottom  30 . Bowden cable wire  10  includes a Bowden cable wire bullet  34  at its end, for mounting. Bowden cable wire bullet  34  is mounted in Bowden cable wire seat  42 . Bowden cable wire bullet seat  42  is an integral part of Bowden cable wire cam  44 . Disc  40  also includes disc axle  45 . In the depicted embodiment, these structures are molded plastic.  
         [0034]    Crosshatching indicates the friction surface  46 A of disc  40 . The friction surface  46 A may be any size, shape or configuration, provided that is oriented in relation to Bowden cable wire  10 , Bowden cable wire cam  44  and Bowden cable wire seat  42  such that tension on the Bowden cable will bring the friction surface  46 A into braking engagement with the corresponding friction surfaces (shown below) on braking actuator housing halves  22  and  30 .  
         [0035]    Disc  40  also includes holes  47 . These holes receive insertion of lever pins  29 . The edges  48  of holes  47  are loading surfaces against which pins  29  will exert rotational force when lever  20  is turned.  
         [0036]    [0036]FIG. 4 is a top view of disc  40  removed entirely from the breaking actuator housing but still engaged with Bowden cable  4 . From Bowden cable sleeve  16 , Bowden cable wire  10  extends to where Bowden cable wire end bullet  34  is seated in wire bullet seat  42 , which is molded into Bowden cable wire cam  44 . Edges  48  define holes  47  for receiving insertion of the pins (not shown in FIG. 4) that exert rotational pressure upon turning of the lever (also not shown in FIG. 4). Crosshatching indicates friction surface  46 .  
         [0037]    [0037]FIG. 5 is a side view of disc  40  removed from the braking actuator. Visible are disk axle  45 , the Bowden cable wire cam  44 , Bowden cable wire  10  and Bowden cable wire sleeve  16 . FIG. 5 depicts an embodiment in which the annular surfaces of disk  40  outside the Bowden cable wire cam  44  are angled or wedge shaped. A portion of these surfaces of disk  40  comprises a frictional surfaces not visible in FIG. 5.  
         [0038]    [0038]FIG. 6 is a schematic, cut away side view of the interaction between the frictional surfaces of the braking actuator. Disk  40  includes frictional surfaces  46 A and  46 B. The cross sectional profile of disk  40  may be any of a wide variety of shapes. In the depicted embodiment, the angles of the edges of disk  40  comprise a wedge shape where the frictional surfaces of  46 A and  46 B are. Complementary angles in the top and bottom of the housing form a wedge seat, which is created by assembly of housing bottom half  30  with housing top half  22 , sandwiching the disk  40  between them.  
         [0039]    In operation, when tension on Bowden cable  10  draws disk  40  into the wedge shape frictional seat  36 , as indicated by arrow F 1 , frictional surfaces  36 A and  36 B and frictional surfaces  46 A and  46 B come into contact and prevent rotation of disk  40 . Accordingly, further motion of Bowden cable wire  10  relative to Bowden cable sleeve  16  is braked. Consequently, any further motion of the continuously positionable ergonomic support attached to the Bowden cable is also braked. When an opposite force indicated by arrow F 2  lifts frictional surfaces  46 A and  46 B away from frictional surfaces  36 A and  36 B, creating gap  32  between them, the disk  40  is free to turn within housing  30 - 22 . When disk  40  is free to turn, it is correspondingly free to increase or release tractive force on Bowden cable wire  10  through a Bowden cable wire sleeve  16  and, correspondingly, move the ergonomic support.  
         [0040]    [0040]FIG. 7 is a schematic top view of the disk  40  illustrating the mechanical advantage given to the braking action by the disk&#39;s design. When the friction surface  46  is placed outboard of the Bowden cable wire cam  44 , its greater radius R 2  from the axle  45  of the disk  40  gives it a greater leverage than the wire, having the shorter radius RI. This represents a mechanical advantage over prior art braking or clutch actuators, wherein the cable wire attachment typically has the same radius as any brake or clutch and in some cases has a smaller radius. By building in such mechanical advantage, the same forces can be controlled with less expensive components.  
         [0041]    [0041]FIG. 8 is top/perspective view of the housing lower half  30  and lever  20  with both the housing top half  22  and disk  40  removed. Visible in housing  30  are the oval disk axial mount  50 , frictional surface  36 B and pin slots  52 . Unlike holes  47  in disk  40 , pins slots  52  in housing lower half  30  do not have edges that are intended to be acted upon by the pins  29 . No loads will be transferred through the edge of pins slots  52 . Rather, these slots simply allow access of the pins  29  through housing lower half  30  to the loading surfaces  48 , the edges of holes  47  in disk  40 . This is self evident by the length of pin slots  52  and their curvilinear coordination with the axis of rotation of the lever  20  to which lever pins  29  are attached.  
         [0042]    Oval disk axle mount  50  allows disk  40  to move a sufficient amount in order that the action of lever  20  through lever pins  29  may raise disk  40  out of braking contact with the frictional surfaces  36 B and  36 A (not shown in FIG. 8). In the depicted embodiment, the preferred orientation of the oval is with its long axis generally perpendicular to the frictional surfaces  36  and  46 , in order to provide room for lifting disk  40 . Although an oval is the depicted embodiment, any shape that does not constrain disk axle  45 , and that allows its movement away from the braking contact of the friction surfaces, may be used.  
         [0043]    [0043]FIG. 9 is a schematic top view of the disk  40  and lever  20 . Pins  29  are fixedly attached to lever  20 . They extend upwards (out of the page in FIG. 9) through pin slots  52  (not shown) and housing bottom  30  (not shown) and into holes  47  in disk  40 . Upon rotation of lever  20  by a user/seat passenger, pins  29  come into engagement with the edges  48  of holes  47  in disk  40 , which edges  48  act as load bearing surfaces for the forces of the lever  20  on the disk  40 . When the lever is pushed in the direction indicated by arrow F 3 , the force indicated by arrow F 3  disk is exerted on disk  40  rotating it in the direction of torque M 3 . When the lever is acted upon with force in direction F 2 , pins  29  exert a force F 2  disk on disk  40 , rotating it with a torque in direction M 4 .  
         [0044]    It is within the scope of the present invention that various embodiments of the invention may vary the relative leverage asserted by each of pins  29  in a variety of ways. First, lever  20  may be mounted on housing  22 / 30  in a variety of ways, including an annular detent and boss arrangement, a centered axial rotational fixation, or an eccentric fixation to the housing. In the depicted embodiment, holes  47  are elongated, to allow some movement of pins  29  in them. The long axis of holes  47  in the depicted embodiment are nonparallel, in order that the pins  29  may engage edges  48  more immediately and reduce any perceived response delay or “slack” to the users touch, while still allowing the disk to be lifted out of the brake seat of the housing. It is within the scope of the present invention that the number of pins, pin location, orientation, degree of leverage, as well as the size, shape, location, orientation and relative relation of holes  47  may be altered in varied embodiments.  
         [0045]    In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained.  
         [0046]    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.  
         [0047]    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.