Abstract:
A walker having a frame and wheel system for use indoors or outdoors, with a wheel assemblies allowing for maintaining substantially level performance over uneven surfaces or obstacles. The wheel assembly includes four wheels in a triple pivot, dual offset configuration. With three pivots and the offset axle configuration, the wheel assemblies allow for substantially even contact with all four wheels of the assembly, with weight substantially balanced on each of the four wheels, during use over uneven surfaces, obstacles, or irregularities.

Description:
[0001]    This application is related to and claims the benefit of U.S. Provisional patent application Ser. No. 61/316852 that was filed on Mar. 24, 2010, which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention generally relates to walkers and other wheeled devices. More specifically, the present invention relates to improvements in wheel assembles, which assist in traversing obstacles and uneven surfaces. 
         [0003]    There are a growing number of citizens that need the assistance of a walker. As this group of people move about, they will encounter irregularities in the terrain such as door thresholds, area carpets, abrupt floor height transitions, cracks in sidewalks, driveways, curbs/gutters, and streets. Parking lots often accumulate debris such as stones, sticks, and other obstacles that can block the wheel and cause an interruption to the forward progress of the walker. Many of these obstacles are overlooked as the users focus more on the physical movement and support of their bodies. Under these situations, there can be a significant risk of an imbalance or even a fall. 
         [0004]    Typical walker designs, as depicted in U.S. Pat. No. 4,135,535, U.S. Pat. No. 4,765,355, U.S. Pat. No. 5,020,560, and U.S. Pat. No. 6,068,273, do not address the issue of obstacles or uneven surfaces. Other references attempt to address obstacles and uneven surfaces, albeit unsuccessfully. 
         [0005]    U.S. Pat. No. 6,666,222 B1 to Fattahi et al. (hereinafter ‘Fattahi’) is directed to a rolling walker adapted to negotiate uneven surfaces. Fattahi discloses two wheels on each of the front legs of the walker, using a larger intermediate wheel (Fattahi  FIG. 1 ). By making the low point of this intermediate wheel lower that the low point of the leading wheel (Fattahi col 2, ln 8-11). Fattahi allows the walker to roll over certain obstacles. However, Fattahi suffers from one or more of the handle&#39;s grip height being abruptly raised upward when a wheel rolls over an obstacle. Fattahi also suffers from not being able to maintain a substantially level profile of the walker grip height. For instance, when a wheel rolls through a drop or depression, the result is a corresponding drop in grip height. Therefore, Fattahi does not adequately address the hazards that a number of users would still face. 
         [0006]    U.S. Pat. No. 6,609,719 B2 to Heien (hereinafter ‘Heien’) is another reference directed to a walker, which unsuccessfully attempts to address obstacles and uneven surfaces. Heien discloses a wheel assembly with a primary wheel and four secondary wheels arranged on the primary wheel (Heien  FIG. 1  and  FIG. 2 ), wherein the secondary wheels are to allow for traversing of some obstacles. Because this system utilizes a fixed primary wheel, Heien suffers from the same problems as Fattahi. The walker grips are likely to raise abruptly when a wheel comes into contact and rolls over an obstacle. Similarly, the walker grips are likely to drop abruptly when the leading wheel enters a surface depression, leading to hazardous conditions for walker users. 
       SUMMARY 
       [0007]    In order to better address obstacles or uneven surfaces, one form of the invention utilizes one or more wheel assemblies, wherein each wheel assembly has offset, multi-tracked wheels, wherein the multiple tracks move with respect to the walker with three pivots. 
         [0008]    The three pivots allow a walker to more effectively negotiate obstacles and other surface conditions, than a typical walker. More specifically, the three pivots allow for a smaller variance in walker grip height compared to the prior art walkers, when the wheels come into contact and roll over an obstacle or an uneven surface. 
         [0009]    With the addition of the offset wheel configuration, the walker further allows for the downward force of the walker to be better distributed among the wheels compared to the prior art walkers. Each wheel travels on its own path, resulting in improved stability over the prior art. 
         [0010]    Because of these improvements, the resulting impedance to forward motion is reduced. Additionally, the decrease in grip height variance over the prior art helps provide for a more stable use of the walker. Finally, the multiple wheel tracks provide lateral stability to lessen the chance of tipping over the prior art. Therefore, the walker reduces the chance of falls and instills confidence in walker users. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of one form of the walker described herein; 
           [0012]      FIG. 2  is an enlarged perspective view of the wheel assembly of the walker in  FIG. 1 ; 
           [0013]      FIG. 3  is a front perspective view of a radial cross-section of a wheel of the wheel assembly in  FIG. 2 ; 
           [0014]      FIG. 4  is an exploded perspective view of the wheel assembly in  FIG. 2  and its component parts; 
           [0015]      FIG. 5  is an enlarged top plan view of the central hub of the wheel assembly in  FIG. 2 ; 
           [0016]      FIG. 6  is an enlarged top plan view of a form of the wheel assembly in  FIG. 2 ; 
           [0017]      FIGS. 7A ,  7 B,  7 C are side views of the wheels of the wheel assembly in  FIG. 2  as the wheels encounter, traverse, and leave an obstacle or uneven surface condition; and 
           [0018]      FIG. 8  is a perspective view of an alternative form of a wheel assembly, utilizing a central hub of an alternate form. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]      FIG. 1  illustrates one form of the walker. The walker  10  includes a frame, which includes various support sections, such as a-shaped side members  14  with legs  12  and horizontal supports with hand grips  16 . Two wheel assemblies  20  are located on the front and bottom of the walker  10 . each wheel assembly  20  can be connected to a front leg  12  of the walker  10 . 
         [0020]    Referring to  FIG. 2 , the wheel assembly  20  attaches TO a walker leg through a hollow post  22 , the hollow post  22  extending upward from the wheel assembly  20  and connecting to the walker leg  12  ( FIG. 1 ). The hollow post can be connected and secured to the walker leg by any suitable device, for example through use of a typical spring-biasing pin (not shown) that is secured within one of several openings (not shown) to allow for height adjustment. 
         [0021]    Referring to  FIGS. 4 and 5 , an end cap  24  slidably mounts into the lower end of the post  22 . Apertures  26  and  27  run laterally through both the lower end of the post  22  and the mounted end cap  24 . The openings of the apertures  26  and  27  on both the post  22  and the end cap  24  are elongated horizontally. The apertures  26  and  27  allow for slidable placement of a rod  28  through both the end cap  24  and the post  22 . The post  22  further includes an adjuster, such as a knob screw  80  which runs through the post  22  and into a wall of the end cap  24 , thereby allowing for the end cap  24  to be secured within the post  22 . The knob screw  80  in conjunction with the horizontally elongated aperture openings on the post  22  further allow for adjusting the rotational alignment of the rod  28  and wheel assembly with respect to the walker  10  ( FIG. 1 ). Because of the elongated shape of the apertures  26  and  27 , the rod  28  and end cap  24  can rotate with respect to the post  22 , which allows for adjustment of the toe of the wheels, the adjustment secured by the knob screw  80 . As shown in  FIG. 5 , by loosening the knob screw  80 , the central hub  30  through its connection with the end cap  24  can be rotated to an optimal position, thereby effectuating toe alignment adjustment  82 . 
         [0022]    Referring to  FIGS. 4 and 5 , a central hub  30  is pivotally connected to the bottom of the post  22 . The central hub  30  can be in the form of a stamped bracket as depicted in  FIG. 4 . The central huh can be of other similarly suitable forms, not limited to molded, machined, cast, or die cast versions of the bracket depicted in  FIG. 4 . Holes  32 ,  32 A on either side of the central hub  30 , allow for the rod  28  to slide through one side of the central hub  30 , then through the post  22  and end cap  24 , and finally through the other side of the central hub  30 . The rod  28  can be secured by securing device such as retaining clip or a cotter pin  29  as depicted in  FIG. 4 . The central hub  30  pivots about the rod  28  and the lower end of the post  22 . 
         [0023]    Referring to  FIG. 5 , the central hub  30  has a rhomboid shape  33 . The rhomboid shape  33  allows for offset connections of a first arm  46  and a second arm  40 , as seen in  FIG. 4 . The offset connections allow for the wheels  60  and  66  ( FIG. 4 ) to be extended further from the post  22 , which increases the pivoting range of the arms  40  and  46  and the central hub  30  about the post  22 , the pivoting range limited by wheels  60  and  66  coming into contact with the post  22 . With an increased pivoting range, the walker can traverse surfaces having greater vertical contours. 
         [0024]    The first arm  46  ( FIG. 4 ) pivotally connects to the more forward edge  34  of the central hub  50 , and a second arm  40  pivotally connects to the more rearward edge  35  of the central hub  30 . Both connections can be accomplished with any suitable fastener, such as a bolt  42  and nut  44 , connected through apertures near the ends of both the first arm  46  and the second arm  40 . The offset configuration  50  shows the first arm  46  being more forward than the second arm  40 . Both the first arm  46  and the second arm  40  have a longitudinal orientation, wherein longitudinal is defined as being in the direction of normal travel of the wheels as they roll forward or backward. The first arm  46  and the second arm  40  pivot about their respective pivotal connections, with vertical movement supplied by the pivoting central hub  30 . 
         [0025]    Unlike a typical walker wheel assembly, which has one wheel, the wheel assembly  20  has four wheels  60 ,  62 ,  64 , and  66 . Two wheels  64  and  66  are rotatably connected to opposite sides of the first arm  46  as shown in  FIG. 4 , as opposed to being connected on the same side of the first arm  46 . Similarly, wheels  60  and  62  are rotatably connected to opposite side of the second arm  40 . Each wheel may be fastened by any suitable device. In another form, wheels can be connected to the same side of an arm. In yet another form, the wheels can be connected so that the wheels of an arm are longitudinally aligned in the direction of travel. 
         [0026]    Referring to  FIG. 6 , the wheels  60 ,  62 ,  64 , and  66  are offset in two directions. The offset arms  40  and  46  translate a similarly offset longitudinal configuration in the respective wheels. Additionally, because the wheels are mounted on opposite sides of each arm  40  and  46 , the wheels  60 ,  62 ,  64 , and  66  have an offset transverse configuration, wherein transverse is defined as perpendicular to the direction of normal travel of the wheels. As a result of the transverse configuration, each wheel  60 ,  62 ,  64 , and  66  rolls in a separate path, or track. The offset orientation in two directions, and thus four surface contact points, can allow for greater stability in both the longitudinal and transverse directions and minimize the chance of the walker tipping over. Furthermore, the offset orientation improves the chances that not all of the wheels  60 ,  62 ,  64 , and  66  will encounter the same obstacle, thereby decreasing the frequency of occurrences where the walker grips would rise up. 
         [0027]    The wheels of the wheel assembly  20  can have a narrowed contact edge, or v-shape as show in  FIG. 3 , wherein the wheel is narrow at the circumference than at the center of the wheel. By reducing the surface contact area, the wheels have an improved chance of avoiding obstacles altogether. Furthermore, a narrower edge profile can lower rolling resistance and can further improve traversing capability over a more standard, flat edged wheel found in typical walkers. However, the wheels can be of any other suitable form, for example wheels that have a flat contact surface or even inflatable wheels. 
         [0028]    The wheels of the wheel assembly  20  can be selected based on their suitability for the intended surface. For instance, if more cushion or shock absorption is desired, a more resilient wheel material than what is ordinary found in a typical walker, can be utilized. 
         [0029]    Referring to  FIG. 8 , while one form of the central hub  30  is shown in  FIG. 4 , the central hub can be any suitable form that preferably allows for pivoting at the lower end of a walker and pivotal attachment of the arms. For example, in  FIG. 8 , the central hub can be in the form of a rotating lever  72  without the need for a structural form similar to the stamped bracket shown in  FIG. 4 . The rotating lever  72  is mounted within a bifurcated end cap  74 . the bifurcated end cap  74  which slides into the lower end of the hollow post  76 . Due to the difference in mounting the rotating lever  72  from the slidably mounted rod  28  in the form shown in  FIG. 4 , the post  76  has vertical slots  78  on either side for the rotating lever  72  to move through during mounting of the bifurcated end cap  74  which contains the rotating lever  72 . The vertical slots  78  culminate at their respective upper portions with a more horizontally elongated opening  79 . The arms  40  and  46  are pivotally connected to opposite ends of the rotating lever  72 , but in an offset configuration as shown in  FIG. 8 . 
         [0030]    Because walkers can have slightly differing sizes, tolerances, or precision imperfections in their build quality, a toe alignment problem can result, where the wheels do not run properly in a straight ahead direction. As briefly discussed previously, the central hub  30  and  72 , as shown in  FIG. 4  and  FIG. 8  respectively, allows for rotational, or toe alignment adjustments, through use of an alignment adjustment tightener, for example a knob screw  80 , in order to more properly point the wheel assembly  20  in a straight ahead direction. For example, by loosening the knob screw  80  ( FIG. 8 ), which mounts through aperture  84 , on post  76 , the end cap  74  can be turned to align the wheel assembly. After a suitable alignment has been obtained, the knob screw  80  can be tightened to secure the assembly position. 
         [0031]    Referring to  FIG. 7 , the wheel assembly  20  can operate in the following manner. The pivot involving the first arm  46 , allows for the front wheel  66  to raise upon contact with an obstacle, while the other three wheels  60 ,  62 , an  64  continue rolling ( FIG. 7A ). The leading wheel of the second arm  40 , which is likely the next wheel in succession, comes into contact with the obstacle ( FIG. 7B ). Upon this contact, the second arm  40  pivots upward. The pivoting central hub  30  allows for the entire wheel assembly  20  to then tilt upward to further assist in traversing the obstacle, while maintaining level walker grips  16  ( FIG. 1 ). Because the wheel assembly  20  can tilt through the central hub  30 , the walker  10  can maintain a more level performance. Also, because the wheel assembly  20  can tilt downward through the central hub  30  ( FIG. 7C ), the walker  10  allows for more level performance over surface depressions ( FIG. 7C ). 
         [0032]    The wheel assembly  20  thus can allow for each wheel  60 ,  62 ,  64 , and  66  to remain substantially in contact with the irregular surface, as depicted in  FIG. 7A ,  7 B, and  7 C. Additionally, the wheel assembly can reduce the vertical movement sensed by the user of the walker  10  through the handle grips  16 . As an added benefit, the downward force exerted by the user of the walker  10  is distributed over four wheels  60 ,  62 ,  64 , and  66  on each side of the walker  10 , resulting in a reduced impedance to forward travel. Furthermore, the multi-tracked assembly ( FIG. 6 ), where each wheel rolls in its own path, transverse (sideways) directions. 
         [0033]    While the wheel assembly has been described and depicted for use with a walker  10 , the wheel assembly may be applied for other wheeled apparatus where these characteristics would be beneficial, such as child strollers, aerospace, landing gear wheels, ATV&#39;s, instrumentation casters, or other applications.