Abstract:
A hydraulically adjustable walker including a frame that includes a plurality of telescoping legs and a leg adjustment assembly that includes at least one valve and at least one tube that delivers hydraulic fluid into the legs and allows a user to control the length of each leg. The legs of the walker are hydraulically adjustable, so that the front legs may be shortened and the back legs extended, or two side legs shortened and the two opposing side legs extended, so as to allow the walker to be securely placed on two different steps.

Description:
BACKGROUND INFORMATION 
     Field of the Invention 
     The invention relates to walkers and other similar devices that assist people in the act of walking and climbing stairs. 
     Discussion of Prior Art 
     The conventional walker is a well-known device that has a U-shaped frame formed by two pairs of legs that define the sides of the walker, each pair having a front leg and a rear leg that are connected at the top by a grip bar and a crossbar that connects the two front legs, thereby forming an opening or well for a person to stand in. The walker is typically about waist high, with the front slightly wider than the width of the user. The two sides are approximately 12 inches deep at the grip bar, i.e., the front and rear legs are approximately 12 inches apart at the top, but the distance between the legs gradually increases in the direction of the floor, for reasons of stability. A user uses the walker by standing in the well, gripping the grip bar, and pushing or moving the walker forward approximately the distance of a normal step, and then stepping into the well, to repeat the pushing motion, all the while holding on to the grip bars. 
     While the standard walker works well on flat and smooth surfaces, it is not as useful when climbing stairs, because the distance between the front and rear legs is significantly greater than the depth of a step on a standard staircase. The fact that the legs of the walker don&#39;t all fit on a single step makes it difficult for a user to pause for a rest when going up or down a staircase. When ascending a staircase, the user can lean into the walker for support, but descending a staircase with a walker is a treacherous adventure for the user, because the walker is always in danger of tumbling down the stairs, unless the user holds it in place. Manual adjustments to the lengths of the legs are sometimes possible, however, this requires a tedious process of turning the walker upside down and manually adjusting each leg. In effect, using a conventional walker on a staircase requires more strength, balance, and skill than the typical user is able to exert. 
     Some walkers deploy mechanical systems to raise or lower the front or rear legs, and this allows the walker to remain in a stable position while supported on two adjacent steps. However, these walkers only allow for the front legs or the rear legs to move in tandem and do not allow for individual leg movement or side-only leg movement. The known walkers also implement mechanical mechanisms that include relatively heavy equipment and are often cumbersome to operate. 
     What is needed, therefore, is a light weight walker with legs that are independently adjustable. What is further needed is such a walker that is easy to operate. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is a hydraulically adjustable walker having a plurality of legs that are independently adjustable and in which the front legs, rear legs, or side legs may be easily adjusted in pairs to, for example, climb or descend stairs. In the embodiment shown the walker according to the invention is a traditionally shaped walker with telescoping legs, making it possible to position the walker on two steps, either with the front legs on one step and the rear legs on a lower step, or sidewise, with one side on one step and the other side on the lower step. Depending on the width of the stairs it is possible that additional steps may separate the legs. Tubes that are filled with a non-compressible, i.e., hydraulic, fluid, such as water, extend through the frame and into the legs. Each of the four legs has telescoping ends that provide for enough extension to span the height of any reasonably spaced steps. 
     The tubes are pre-filled with an amount of hydraulic fluid that is sufficient for all four legs to be extended to the same length for normal walking. The tubes extend through the upper portion of the frame and extend into the upper telescoping end of the each telescoping leg, allowing the fluid to move between any and all legs. The tube ends in the upper section of the telescoping leg allowing the fluid to pass into the lower extension and forcing the telescoping section to extend. In this mode, the grip bars on the walker are approximately as high as the user&#39;s waist. Handgrips are provided on the grip bars and valves are provided near the hand grips to control the flow of fluid through the tubes. Closing the valves prevents the fluid from flowing from one leg to another, thereby locking the legs in position. Opening the valves allows the fluid to flow through the tubes and into, or out of, the telescoping leg extensions. 
     To adjust the length of the legs the user opens the valves and then applies a small amount of pressure to the walker in the direction that he wishes to shorten the legs. For example, to walk straight up a set of stairs, the user opens the valves and leans forward on the walker to force the front legs to compress inward. Shortening the front legs causes the rear legs to extend outward the corresponding length. The user then lifts the walker on to a first set of steps, with the front legs resting securely on the higher step and the rear legs resting firmly on the lower step. When used on a standard size stair case, the device is sized such that one step separates the retracted legs from the extended legs. The user then closes the valves to lock the fluid in position and steps onto the staircase. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. The drawings are not drawn to scale. 
         FIG. 1  is a front view of the walker according to the invention in the normal walking position. 
         FIG. 2  is a side view of the walker in the normal walking position. 
         FIG. 3  is a side view of the walker with the front legs retracted and the rear legs extended, placed on a staircase. 
         FIG. 4  is a front view of the walker with one set of side legs extended and the other retracted, placed sideways on a staircase. 
         FIG. 5  is a top view of the walker. 
         FIG. 6  is a side view of the upper portion of the device showing a portion of the valve system. 
         FIG. 7  is a side view of the upper section of the telescoping leg. 
         FIG. 8  is a side view of the middle section of the telescoping leg. 
         FIG. 9  is a side view of the lower section of the telescoping leg. 
         FIG. 10  is a cross-sectional view of a leg in an extended position. 
         FIG. 11  is a cross-sectional view of a leg in a retracted position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully in detail with reference to the accompanying drawings, in which the preferred embodiments of the invention are shown. This invention should not, however, be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art. 
       FIGS. 1-6  illustrate a hydraulically adjustable walker device  100  according to the invention comprising a frame  10  with length-adjustable legs  30  and a fluid delivery system  60  for changing the lengths of the legs  30 . The frame  10  includes upper sidebars  12 , middle sidebars  14  and lower sidebars  16  along with upper crossbar  18  and lower crossbar  22 . The sidebars  12 ,  14 ,  16 , connect a front length-adjustable leg  30  to a rear length-adjustable leg  30 , and the crossbars  18 ,  22 , connect the front length-adjustable legs  30 , forming an opening or well for a person to stand in. Hand grips  24  may be provided for the user&#39;s comfort and safety. In normal use, the user grips the hand grips  24  and walks into the well of the walker, pushes or picks up the walker and moves it a short distance forward, and then walks forward to place him- or herself in the well again. 
     The fluid delivery system  60  includes a series of tubes  62  that are filled with a non-compressible, i.e. hydraulic, fluid (not shown), valves  64 , and activation levers  66 . The tubes  62  extend through the middle sidebars  14  and into the top of the length-adjustable legs  30 . Another tube  62  connects the tubes  62  in the middle sidebars  14 , allowing fluid to pass from one length adjustable leg  30  to any other leg  30  or legs  30 . 
     The valves  64  control the flow of fluid through the tubes. When the valves  64  are closed the fluid is unable to move and the legs  30  are effectively in a locked position and unable to change in length. Opening the valves  64  allows the fluid to move through the tubes  62 . The activation levers  66  allow a user to easily open and close the valves  64 . 
     Once the levers are open a user is able to adjust the height of the legs  30  by applying a small amount of pressure in the direction of the leg  30  or legs  30  he wishes to retract, which forces the hydraulic fluid out of the retracted leg  30  or legs  30  through the fluid delivery system  60  to the other legs  30  which are then forced to extend. The tubes  62  are pre-filled with an amount of hydraulic fluid that may vary depending on the desired height of the device  100 . 
     Each telescoping leg  30  includes an upper section  32 , middle section  34  and lower section  36 . As the fluid flows through the tubes  62  into the upper section  32  of the leg  30  it exits the tube  62  and passes through the upper section  32 , into the middle section  34  and then into the lower section  36  until it reaches the bottom of the lower section  36 , which is closed, at which point the lower section  36  telescopes outward, thereby extending the length of the leg  30 . As the user continues to apply pressure to legs that are to be retracted, the lower section  36  of the legs to be lengthened continues to extend until it has reached its limit, at which time the middle section  34  begins to extend. Once the desired leg length is reached the user stops applying pressure and turns the levers  66  to close the valves  64  to lock the walker  100  into the desired position. 
       FIGS. 7-11  illustrate the telescoping legs  30 , including the upper leg section  32 , the middle leg section  34  and the lower leg section  36 . The upper section  32  is fixedly attached to frame  10 . The tube  62  extends out from the frame  10  into the upper section  32 . The middle section  34  has an open upper end  38  that fits over upper section  32  and an open lower end  42  that fits within the lower section  36 . Common seals (not shown), such as O-rings, are provided on each end to allow for watertight movement of the middle section  34 . The lower section  36  has an open upper end  44  and a closed lower end  46 . The lower end  46  supports the device  100  on the walking surface and may be covered with a rubber pad or other device or substance that is intended to provide a grip or buffer beneath the device  100 . The upper end  44  for the lower section  36  fits over the lower end  42  of the middle section  34  and has a common seal (not shown) such as an O-ring to support water-tight movement of the lower section  36  over the middle section  34 . 
     The embodiment shown includes two front legs  30 , two rear legs  30 , and three levers  66 A,  66 B,  66 C and three valves  64 A,  64 B,  64 C. If the user wants to adjust the device frontwards or backwards only valves  64 A and  64 B need to be opened in order to allow the fluid to pass from a front leg to a rear leg or vice versa. If the user wishes to compress one side of the device  100  the third valve  64 C also needs to be opened to allow the fluid to pass from one side to the other. Similarly, if the user wishes to retract one leg  30  while extending the other three legs  30 , each valve is opened and the user applies pressure in the direction of the one leg  30  to retract that leg  30 . The fluid flows into the other three legs  30 , causing them to extend a proportional fraction of the distance the one leg has been shortened. The number of valves  64  may vary, depending on the degree of control that is desired. The frame  10  is foldable and guide tracks  26  allow the sides of the frame to fold in towards the front of the frame for ease of storage. 
     A lightweight overflow water tank (not shown) may be provided to allow for the easy addition or removal of water from the leg extension mechanism. The ability to change the volume of fluid in the delivery system  60  enables easy adjustment of the normal height of the walker, so that the same walker may be comfortably used by people of different heights. The tank is affixed to the frame and may be any suitable container that holds water. The tank has an opening to allow for the addition or removal of water, and is connected by a tube to the fluid delivery system  60  and an additional valve to allow the user to turn the flow of water on and off. 
     It is understood that the embodiments described herein are merely illustrative of the present invention. Variations in the construction of the walker may be contemplated by one skilled in the art without limiting the intended scope of the invention herein disclosed and as defined by the following claims.