Abstract:
A stair walker device for aiding ambulatory persons in ascending ad descending stairs, ramps and other uneven walkable surfaces. A pair of hand-controlled levers used separately or together to adjust the front legs, by controlling the extension or retraction of a pair of front leg portions. The rear legs are adjusted for the user&#39;s height once only by suitable adjustable fastening. The sides of the stair walker frame can be readily folded for storage or for carrying.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a collapsible, four-legged walker aid apparatus for those persons requiring walkers to travel on either level or inclined ground, and to negotiate stairs. The stair walker has four extendable and retractable vertical legs, with each of the front two legs being made up of three concentric tubes controllable by individual hand control levers and cables, to extend or retract the front pair of legs simultaneously. 
     2. Description of Related Art 
     References 
     
       
         
               
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 5,649,558 
                 07/97 
                 Richard 
                 135/97 
               
               
                   
                 4,411,283 
                 10/83 
                 Lucarelli 
                 135/97 
               
               
                   
                 3,176,700 
                 04/65 
                 Drury 
               
               
                   
                 5,636,651 
                 07/97 
                 Einbinder 
                 135/97 
               
               
                   
                 2,708,473 
                 05/55 
                 Gable, et al. 
               
               
                   
                 3,387,618 
                 06/68 
                 Swann 
               
               
                   
                 3,421,529 
                 01/69 
                 Vestals 
               
               
                   
                 4,094,331 
                 06/78 
                 Rozsa 
               
               
                   
                 5,740,825 
                 04/98 
                 Brunengo 
                 135/67 
               
               
                   
                 5,349,977 
                 09/94 
                 Wood 
                 135/67 
               
               
                   
                 5,603,517 
                 02/97 
                 Lorman 
               
               
                   
                 4,995,412 
                 02/91 
                 Hirn et al. 
                 135/67 
               
               
                   
                   
               
             
          
         
       
     
     The related art of interest shows various stair walkers and mechanisms for extending and retracting walker appendages. The related art will be discussed in the order of perceived relevance to the present invention. 
     U.S. Pat. No. 5,649,558 issued on Jul. 22, 1997, to Reginald L. Richards describes an accommodation walker having four legs with shortening of the front pair of legs occurring by separate hand controls to manipulate an externally exposed rack and gear control through exposed cables. The front legs are lengthened only by gravity when the racks and gears are disengaged. A reversible motor may be substituted for the rack and gears mechanism. The rear legs may be shortened by spring loaded push buttons (not shown) that cooperate with extension holes. The walker is distinguishable by its reliance on separate hand controls for the front pair of extendable legs for shortening by the non-equivalent exposed cables, rack and gear controls and motor, i.e., both handles are necessary. The front legs are lengthened manually with the aid of gravity. The present invention hides the cables and spring mechanism by the use of three tubes. Additionally, there is no suggestion for folding the walker in the manner taught in the present invention. 
     U.S. Pat. No. 3,455,313 issued on Jul. 15, 1969, to Harold L. King describes a four-legged walker with two arcuate cross braces. Each leg has an overlapping apertured leg extension mechanism that is extendable by a spring which is released by a right and left hand grip housing two pins traveling in slots in either the pipe or the handgrip. A cable from the hand-grip retracts a semicircular spring connected pin from a hole in the overlapping leg extension. A second coil spring effects the extension of a leg until the pin enters another hole to lock the leg extension. The separate hand-grip mechanisms and the pin locking mechanism are totally different from the single hand possible locking mechanism of the present invention. Additionally, the walker has external legs as opposed to the internal legs of the present invention and is not foldable. 
     U.S. Pat. No. 3,176,700 issued on Apr. 6, 1966, to John H. Drury, Jr. describes a walking aid device consisting of a tubular frame with four legs, and upper arcuate front bar, a U-shaped support bar, and hand grips on the sides of the upper arcuate front bars. The two legs regarded as rear legs have contractible leg portions which telescope into the fixed legs by depressing locking buttons located at the mid-sections of the rear legs and contracting coiled springs. Each adjustable leg is locked in a shortened state by the button accessing another hole in the upper leg. The locking button is motivated by another U-shaped spring. A bolt in an upper leg travels in a slot of the contracting leg to maintain a non-twisting condition. The process of ascending and descending stairs requires the user to rotate the walker 180 degrees. The walker is distinguishable by having only two adjustable legs, a non-folding walker and the requirement for laboriously reaching down for the release button on each leg. 
     U.S. Pat. No. 4,411,283 issued on Oct. 25, 1983, to Frank J. Lacarelli describes an invalid walker formed from tubular aluminum having a telescoping front leg assembly which slides through a pair of guide tubes and is integrated with a cross bar adjustment member. The rear pair of legs have hand grips on an upper medial and integral front support and an additional lower support frame, wherein both supports are clamped to the front guide tubes. The front legs are adjustable in a height range of 2 feet by utilizing a manually movable locking assembly with a clip on each leg which slides into one of 24 slots in the inner surface of the front legs. The lock must be removed first before the clip can be moved along the telescoping leg. A click and drag pin is also located on an inner surface of the guide tube to indicate the movement of the telescoping legs. The rear legs have adjustable foot portions with indexing buttons and elongated feet directed inward. The walker is distinguished by individual locking of only two front legs clips which must be manipulated by hand in a two-step process. Also, the front legs lack springs to motivate either the extension or retraction of the legs. 
     U.S. Pat. No. 5,636,651 issued on Jun. 10, 1997, to Eli Einbinder describes an adjustably controllable walker with two U-shaped tubes with a cross bar and four legs with wheels which can be controlled by an actuator means such as a button, pressure sensor or lever. The actuator may control a stabilizer brake mechanism to engage or release a brake. Lifting the walker can release the brake. A strain gauge or lifters may be provided to respond to the lifting force. The walker is distinguishable by its reliance on wheels and brake mechanisms. 
     U.S. Pat. No. 2,708,473 issued on May 17, 1955, to Harry L. Gable et al. describes a walker with six legs and feet, wherein the middle legs are positioned by set screws acting through collars on upper side bracing members. Anther set of collars on lower side bracing members stabilize the middle pair of extendable legs. The walker is deemed distinguishable by its requirement for six legs and manual adjustment of each middle leg in negotiating a flight of steps. 
     U.S. Pat. No. 3,387,618 issued on Jun. 11, 1968, to David T. Swann describes a walker in the form of a cane or a crutch on a vertical shaft welded to a horizontal yoke member with a pair of pivotal and vertical short legs extendable from a braced upper sleeve portion. The vertical shaft has a pivotal horizontal upper leg with a cross arm which is extendable from a sleeve section. The configuration of the walker thus accommodates three steps. The walker is distinguishable by its three-step stair conforming structure. 
     U.S. Pat. No. 3,421,529 issued on Jan. 14, 1969, to Richard A Vestal describes another three-step stairway walker having a main frame formed from an upper horizontal U-shaped member secured at its middle front portion, and two rectangular and vertical side subframes. Each vertical side subframe has a set of L-shaped leg portions with shorter rear leg portions. The outwardly extending feet are attached vertically to the main frame by a plurality of sleeves with the uppermost sleeve having thumb screws for securing the legs by the user. The front and rear sets of feet are adjusted to conform to the steps. The walker is distinguishable by its three-step structure. 
     U.S. Pat. No. 4,094,331 issued on Jun. 13, 1978, to Peter Rozsa describes a walker for negotiating stairs by ascending in one position and descending by reversing the position of the walker, and walking on a level surface by inverting the walker. The walker consists of two side frames substantially in the form of a rectangle with an indented top portion having a centered rubber or plastic sleeve. A necked and coupled center portion has a leg extending on each side (front or rear) and a pair of handles extending from a region above the necked portion and directly above the extended legs. The extendable legs are apertured sleeves locked by a spring loaded pin. The walker is distinguishable by its reliance on extending only two legs manually instead of automatically. 
     U.S. Pat. No. 5,740,825 issued on Apr. 21, 1998, to P. J. Brunengo describes an articulated walker having a first and second side section, each having a front and rear leg, an upper cross section, and a lower cross section. The side sections are coupled by an upper horizontal cross bar and a lower horizontal cross bar. The walker adjusts for stair height by a pivotal relationship between the upper and lower cross ties and the front and rear legs. Adjustment of the legs is achieved by pulling on handles that release a pin-locked cam mechanism located on the lower cross tie of each side section. The walker is distinguishable by not having individual legs that are adjustable and not maintaining a level upper cross tie for gripping when ascending or descending stairs. 
     U.S. Pat. No. 5,349,977 issued on Sep. 27, 1994, to Maurice Wood describes a kit including four supplemental legs, two actuating bars, and the mechanical means to attach the apparatus to an existing walker for the accommodation of stairs or inclines. The user is able to adjust the front and back legs of one side of the walker by pulling the actuating lever and letting gravity adjust the legs to a desired height. This allows the user to navigate stairs by leaving the walker pointed straight ahead and engaging both actuator bars, or turning the walker sideways and engaging only one actuator bar. This inventions is distinguishable in that it is an attachment to an existing walker and therefore has external components, and also by the ability to control both legs on one side with the one actuator bar but not both front legs with one lever. 
     U.S. Pat. No. 5,603,517 issued on Feb. 18, 1997, to Shmil Lorman describes a rollable and foldable walker frame having a seat, four wheels, and four handles. The wheels can be locked automatically by braking devices. The walker frame comprises a first frame element consisting of two parallel curvilinear tubes with extendable curved handles at the upper ends, and non-extendable wheeled legs at the opposite ends which are connected by a cross bar. A second frame element which is U-shaped in front and with L-shaped sides comprises a foldable seat with non-extendable rear wheeled legs. A third frame element with two parallel inverted L-shaped tubular portions has a second set of height adjustable handles at its upper ends, and its opposite ends are connected to the pair of first frame elements. Two pairs of braking devices are connected to the rear and front legs, each of the braking devices slidably supports one of the wheel mounts over a wheel such that the application on the frame of a downward force urges the braking of the wheels. The walker is distinguishable by its unique braking devices and four wheels. 
     U.S. Pat. No. 4,995,412 issued on Feb. 26, 1991, to Doris Hirn et al, describes a walker with two side sections connected in the front by two horizontal cross bars. The device is able to be transformed into a cane and is also adjustable for people of varying height and width. The walker is distinguishable by needing manual adjustment for ascending or descending stairs. 
     None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a foldable four-legged walker aid apparatus for those persons requiring walkers to travel on either level ground or inclined ground, and to negotiate both the ascent and descent of stairs. The stair walker has four extendable an retractable vertical legs, with the front two legs each being made up of three concentric tubes controllable by individual hand control levers and cables, to extend or retract the front pair of legs simultaneously. Each control lever controls both front legs, affording the advantage that a user with impaired use of one upper extremity may use just one hand to control both front legs. 
     Accordingly, it is a principal object of the invention to provide a four-legged walker aid apparatus with a pair of adjustable front legs and a pair of adjustable rear legs. 
     It is another object of the invention to provide a four-legged walker aid apparatus for traveling on either level ground, inclined ground, or in negotiating stairs. 
     It is a further objective of the invention to provide a four-legged walker aid apparatus wherein the pair of front legs can be automatically extended and retracted by hand control, and the height of the pair of rear legs can be adjusted manually. 
     Still another object of the invention is to provide a four-legged walker aid apparatus which is foldable for storage or for transporting the device, such as in a car or on escalator stairs. 
     Yet a further object of the invention is to provide a four-legged walker aid apparatus with one size which can accommodate persons of any height by adjustment of the P-shaped rear frame elements within the bracket holding each of the P-shaped rear frame elements to the front leg frame element. 
     It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purpose described which is inexpensive, dependable, and fully effective in accomplishing its intended purposes. 
     These and other objects of the present invention will become readily apparent upon further review of the following specifications and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a folding stair walker apparatus according to the present invention. 
     FIG. 2 is a schematic side view of a user traversing a flight of stairs in an ascending position and a descending position with the aid of the walker. 
     FIG. 3 is an enlarged scale, left side view of the walker demonstrating height adjustment of the walker by utilizing the brackets which hold the P-shaped rear frame elements to the front frame element. 
     FIG. 4 is an elevational, partially sectional and fragmentary front view of the handle controls and the front legs for operating the extension and retraction of the adjustable legs. 
     FIG. 5 is an elevated side view of an adjustable front leg showing the relaxed spring with the inner leg tube having the spring loaded button, omitting the middle tube, and the outer tube being partially broken away. 
     FIG. 6 is an elevated side view of an adjustable front leg showing the contracted spring with the middle tube having a slot for the alignment bolt, and the middle and outer tubes partially broken away. 
     FIG. 7 is an elevated view of an adjustable front leg showing the inner tube and the contracted spring in shadow, the middle tube partially, and the outer tube with the alignment bolt within the slot of the middle tube. 
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention relates to a four-legged walker aid apparatus for those persons requiring walkers to travel on level ground, inclined surfaces, and to negotiate stairs. The stair walker has two extendable and retractable front legs made up of three concentric tubes, each being controlled by either one of a pair of levered hand controls, and two manually height-adjustable rear legs. A pair of side brackets enable further height adjustment between the front legs and the rear legs. The walker aid is designed for accommodating a user of any height. 
     Referring in general to FIG. 1, the stair walker is a self-standing apparatus with a pair of P-shaped rear frame elements  12  and a U-shaped front element  28  with an upper curvilinear crossbar  30  and a lower curvilinear crossbar  32  to add stability. Both the P-shaped rear frame elements  12  and the U-shaped front element  28  house adjustable front  38  and rear  20  leg portions with plastic rubber caps  22  to prevent slipping of the device. The P-shaped rear frame elements  12 , the U-shaped front frame element  28  with upper curvilinear crossbar  30  and lower curvilinear crossbar  32 , and the front  38  and rear  20  leg portions are all made of a light weight metal, such as aluminum, or a fiberglass material. 
     The pair of P-shaped rear frame elements  12  are created by either bending the material to form a P-shape and making a weld or adhesion at the junction  76 , or welding or adhering each corner individually. Resilient hand grips  14  are centered on a top portion of the rear frame elements  12 . Each rear leg sleeve portion  18  contains a series of apertures  21  (in shadow) drilled into one side of the tube to accept a spring-loaded button  24  contained inside the top of each rear leg portion  20 . The apertures  21  are illustrated in FIG.  1  as being on the inside or medial surface of each rear leg sleeve portion  18  but may also be positioned on the posterior or lateral surface of each rear leg sleeve portion  18 . Each rear sleeve leg portion  18  accepts the rear legs  16  in a sliding, telescoping manner. Adjustment of the rear legs  16  is accomplished by pushing in the spring-loaded button  24  and traversing the apertures  21  located on the rear leg sleeve portion  18 . This adjustment is usually made once by the user to match their height requirements and is not changed thereafter by that user. 
     The U-shaped front element  28  with the upper curvilinear crossbar  30  is also made by either bending or welding the individual corners. The lower curvilinear crossbar  32  is either bent or welded at the corners and then attached to the U-shaped front frame element  28  at the front leg sleeve portions  36  by weld or adhesive. The front leg portions  36  of the U-shaped front frame element each contain an inner tube  62  (depicted in FIGS. 5-7) and accept the front legs or middle tubes  38  in a sliding and telescoping manner. The front leg portions  38  contain a series of apertures  39  drilled into the material on only one side that accept a spring loaded button  56  built into the inner tube portion  62  which will be explained fully in the discussion of FIGS. 5-7. The apertures  39  and spring-loaded button are illustrated in FIG. 1 as being on the inside or medial surface of the front leg portion  34  but may also be located on the posterior surface of the front leg portion  34 . The front legs  34  are adjusted using either of the pair of bicycle type control levers  40  and  42  that are positioned on the surface of the upper curvilinear crossbar  30 . The levers  40  and  42  are illustrated in FIGS. 1-4 as being on the front surface of the upper curvilinear crossbar  30  but may be positioned on any surface of the upper curvinlinear crossbar  30 . The levers  40  and  42  are attached to the upper curvilinear crossbar  30  by weld, a bolted bracket, or any other form of adhesion. The levers  40  and  42  together or independently control the extension and retraction of the front legs  34  only, as will be fully explained in the discussion of FIGS. 5-7. 
     Brackets  44  with front fasteners  45  and rear fasteners  46  are utilized to connect the P-shaped rear frame elements  12  with the U-shaped front frame element  28 . The brackets  44  can be loosened or tightened, allowing adjustment of the P-shaped rear frame elements  12  on the U-shaped front frame element  28 , by adjusting the front and rear fasteners  45  and  46 . This allows for an inward folding of the P-shaped rear frame elements  12 , as shown by the arrows, for storage or transport, and also allows the user to adjust the height of the P-shaped rear frame elements  12  without making adjustments to the U-shaped front frame element  28  as shown in FIG.  3 . To increase stability, the brackets  44  may be held in place on the front leg portion  36  by weld or other form of adhesive, allowing only the posterior half of the bracket  44  to be loosened for adjustment using the rear fasteners  46 . The height of the P-shaped rear frame elements  12  are more accurately adjusted by drilling apertures  49  through the front bar portion  47  of the P-shaped rear frame element  12  that accept a metal cotter pin  51  that is run through the posterior portion of the bracket  44 . The brackets  44  can be fabricated out of a hard metal such as steel or a hard plastic and have a rubber lining on the inside to prevent slipping of the front frame element  28  and rear frame element  12  inside of the brackets  44 . 
     FIG. 2 illustrates the convenience of using the walker aid apparatus to negotiate the ascent and descent of stairs  48  by a user  50 . It is important to note that the walker aid  10  need not be reversed for its use in ascending and descending stairs  48 . More importantly, the set of front legs  34  are controlled by the hand levers  40  or  42  in adjusting to a suitable extension or retraction. Moreover, the two front legs  34  are controlled simultaneously by either of the hand control levers  40  (not shown) and  42 . This feature is particularly advantageous for the individual who may have lost the ability to use one upper extremity or hand, either permanently or temporarily. The user  50  can soon judge by experience the preferred extension or retraction of the front set of legs for a given stairway. 
     FIG.  3 . shows the adjustment possible for increasing the height of the P-shaped rear frame element  12  (in shadow) or to decrease the height of the P-shaped rear frame element  12  (not shown) to accommodate a user of greater or lesser height, respectively, by means of the bracket  44  and fasteners  45  and  46 . The height of the P-shaped rear frame element is accurately controlled by lining up the apertures  49  on the front bar portion  47  of the rear frame element  12  with the bracket  44  so that a cotter pin  51  can be inserted through the posterior half of the bracket  44  and the apertures  49 , locking the rear frame element  12  at a set height. The rear leg portion  20  can then be adjusted by lining up the correct apertures  21  on the rear sleeve portion  18 , with the spring loaded button  24  housed in the rear leg portion  20 , in a sliding, telescoping manner, so that walker aid apparatus  10  sits level. This adjustable height feature of the rear frame element  12 , utilizing the bracket  44 , enables a wide range in height of the device to accommodate each user regardless of their height. 
     FIG.  4 . illustrates the part of the front frame element  28  with either the right hand control lever  40  or the left hand control lever  42  controlling the two front legs  34  (FIGS. 1-3,  5 - 7 ) simultaneously. This feature allows one-hand controlled height adjustment of the front legs by the user who may have limited or no use of one upper extremity or hand. This unique control of the adjustment of the front pair of legs  34  is obtained by having a total of four cables, two cables  52  from the right hand control lever  40 , and two cables  53  from the left hand control lever  42 , which cross such that one cable from each lever  40  and  42  traverse down each front leg and ending at the spring-loaded steel button  56  contained in the bottom of the inner tube  62 , which is housed inside of the front leg portions  36  (shown in FIGS. 1-3,  5 - 7 ). Each of the four cables  52  and  53  are inserted into the U-shaped front frame element  28  by drilling holes in the upper curvilinear crossbar  30 . Anyone skilled in the art of such mechanisms will understand that when either hand control lever  40  or  42  is pulled back towards the upper curvilinear crossbar  30 , the cables  52  and  53  will be pulled in a manner that will pull back on the spring-loaded steel button  56  in each leg. 
     The spring-loaded steel button  56  contained in the base of each inner tube  62  is attached to a flat strip of resilient metal  58 , known to those skilled in the art as “spring” metal, that is adhered to the inside of the base of the inner tube  62  at a spot indicated by reference character  60  with any number of strong adhesives, weld, or metal insert. One side of the lower portion of the inner tube  62  must be cut away to allow the spring-loaded button  56  to traverse the apertures  39  located in the middle tubes  38  and the single aperture  74  (FIG. 7) located in each outer tube  36  of the front legs, explained fully in the discussion of FIGS. 5-7. Metal cross pins or screws  54  must be inserted through the base of each inner tube  62  so that the cables  52  and  53  can be passed over the metal cross pins  54  before being connecting to the spring-loaded buttons  56  by weld, screw, or wire fastener. Someone skilled in the art will understand that the metal pin or screw  54  allows a more advantageous direction of pull by the cables  52  and  53  on each spring-loaded button  56 . After inserting the metal pins or screws  54 , the outer surface of the base of the inner tube  62  must be filed smooth of any projections to allow for a smooth sliding, telescoping action of the middle tube or front leg  38  (FIGS. 1-3,  5 - 7 ) over the base of the inner tube  62 . The construction of the spring-loaded button mechanism  56 ,  58 ,  60 , and  54  must be completed prior to the insertion of the inner tube  62  into the front leg sleeve  36  (FIGS. 1-3,  5 - 7 ) of the U-shaped front frame element  28 , which is described in the discussion of FIGS. 5-7. The attachment of the cables  52  and  53  to the spring-loaded button  56  must occur after the inner tube  62  is inserted into the front leg sleeve  36  (FIGS. 1-3,  5 - 7 ) of the U-shaped front frame element  28 . 
     FIGS. 5,  6 , and  7  illustrate the unique three-tube structure of the adjustable front legs  34 . The three tubes include; the inner tube  62  which contains the spring-loaded mechanism for controlling the height of the front leg via the middle tube  38 , the middle tube  38  which has the apertures  39  drilled into one side for the acceptance of the spring loaded button  56 , and the outer tube or front frame sleeve portion  36  which houses the inner tube  62  and middle tube  38 . A coil spring  64  sits between the inner tube  62  and the outer tube  36 , and rests on top of the middle tube  38  to assist gravity when extending the middle tubes  38  when descending stairs. When assembling this three tube structure, first the inner tube  62  is inserted and connected to the outer tube  36  as described in the following paragraph, next the spring  64  is inserted between the inner tube  62  and the outer tube  36 , and finally the middle tube  38  is inserted, also between the inner tube  62  and outer tube  36 . 
     FIG. 5 specifically shows the inner tube  62  with the coil spring in its extended position. The top most portion of the inner tube  62  is attached to the outer tube  36  by a metal pin or rivet  70  that traverses the entire width of the front leg  34 . The metal pin or rivet  70  is also shown in FIGS. 1-3 to indicate the approximate height of attachment for the inner tube  62  within the outer tube  36 . A one inch metal tube insert  72 , taken from the same diameter of tube as the middle tube  38 , is attached to the top of the inner tube  62  by weld or adhesive prior to inserting and attaching the inner tube  62  to the outer tube  36 . This insert serves two purposes; first to take up the space between the inner tube  62  and the outer tube  36  at the site of attachment which makes the attachment more secure, and second to keep the spring  64  from moving into the upper curvinlinear crossbar  30  (FIGS. 1-4) when compressed. FIG. 5 also shows the action of the spring-loaded button mechanism  56 , as it is pulled backwards (in shadow) by the cables  52  and  53  when either of the hand control levers  40  and  42  are pulled. 
     FIG. 6 shows the coil spring  64  contracted as it gets pushed on by the top of the middle tube  38 . The middle tube  38  slides in a telescoping manner between the inner tube  62  and the outer tube  36  to vary the height of the front legs  34  (FIGS. 1-3) for ascending and descending stairs (FIG.  2 ). A longitudinal groove  66  (in shadow) must be beveled into the outer surface of the middle tube  38 , stopping at least two inches from the top of the middle tube  38 . The groove  66  accepts a bolt or screw  68  that is contained in the outer tube  36  which keeps the middle tube  38  from spinning about a vertical axis when extending or retracting. This is necessary to keep the apertures  39  correctly aligned in relation to the spring-loaded button  56  (FIGS. 1,  3 ,  4 - 5 ) to insure locking of each middle tube  38 . The longitudinal groove  66  and alignment bolt  68  can be installed on any side of the front leg  34  that does not directly conflict with the apertures  39  and spring-loaded button  56 . 
     FIG. 7 illustrates the structure of the front leg  34  with all three tubular components. The outer tube or leg sleeve portion  36  accepts the middle tube  38  which compresses the coil spring  64  (in shadow) surrounding the inner tube  62  (in shadow). A bolt  68  is shown traversing the groove  66  (in shadow) for maintaining the alignment of the middle tube  38  with the outer tube  36 , a single aperture  74  is drilled into the outer tube  36  to accept the spring-loaded button  56  as it traverses through any given aperture  39  of the middle tube  38 . This transfers the weight bearing load of the middle tube  38 , as it pushes on the spring loaded button  56 , away from the inner tube  62  and onto the stronger outer tube  36 . 
     In operation, a person first adjusts the stair walker for use on flat surfaces by adjusting the P-shaped rear frame elements  12  at both the brackets  44  and the rear legs  16  until the rear frame elements  12  are at the correct height for that user. When confronted with an incline or going up stairs, the user would first place the front legs  34  onto the elevated surface and then pull one or both hand control mechanisms  40  and  42 . This will cause the cables  52  and  53  to pull on the spring-loaded buttons  56  contained on the inner front tube portion  62  pulling the buttons  56  out of the aperture  74  on the outer tube  36  and the relevant aperture  39  on the middle leg  38 . At this point the middle tube  38  is free to slide between the outer tube  36  and the inner tube  62 . The user will push down on the U-shaped front frame element  28  of the walker aid device causing compression of the coil spring  64  and retraction of the middle tube  38  until the walker is again level. The hand control levers  40  and  42  are then released and the spring-loaded buttons again traverse through the apertures  39  in the middle tube  38  and the aperture  74  in the outer tube  36 , effectively locking the middle tube  38  in place. The user may then proceed up the inclined surface, making any necessary adjustments in the same manner just described. When a flat surface is again reached, the hand control levers  40  and  42  can be pulled with a resulting disengagement of the middle tubes  38 , letting gravity and the coil springs  64  assist in extending the middle tube  38  until the walker is again level. 
     When confronted with a decline or going down steps, the user must pull the hand control levers  40  and  42  while either lifting up on the front frame element  28  or hanging the front legs  34  over the edge of the stair or decline. Pulling of the hand control levers  40  and  42  will again pull on the cables  52  and  53  causing the spring-loaded buttons  56  to pull back and allow free movement of the middle tubes  38 . Gravity and the coil spring  64  will cause extension of the legs until they are either stopped by the surface or step at the desired length, or the terminus of the longitudinal groove  66  is reached by the bolt  68  contained in the outer leg  36 . The hand control levers  40  and  42  must then be released causing the spring-loaded button  56  to re-lock the middle tube  38 . The user then completes the navigation of the obstacle and returns the walker to its neutral, horizontal position. 
     Thus a folding four-legged walker aid apparatus has been shown that enables the user to automatically retract the front legs simultaneously by one or both proximate hand control levers for traversing inclined surfaces or steps. The light but sturdy apparatus can be readily folded for storage or transportation purposes to minimize space requirements. A further advantage results from hand controls which remain in front because the apparatus need not be turned around as is the case with prior art devices. This walker apparatus can accommodate a wide range in height. For example, a very short person can shorten the rear legs of the present invention, lower the rear frame elements by utilizing the brackets, and still have the full adjustment range of the front legs for navigating stairs or angled surfaces. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.