Abstract:
A folding wheelchair is provided which includes first and second spaced-apart posts. A rear wheel is rotatably mounted to each post. First and second spaced-apart side rails are pivotally connected with a respective post. First and second front legs are pivotally connected with a respective side rail having their lower ends extending downwardly. A front wheel is connected with each front leg. A side tensional support member is pivotally connected to each leg and to a respective post. To fold the seat together, the front ends of the side rails are pivoted toward an upper end of the post. To further save space, the rear wheels are rotatively connected to the post by a quick release pin arrangement allowing for their quick removal.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to wheelchairs for disabled persons, and more particularly to a wheelchair that folds to occupy little space while being stored or transported in a vehicle. Still more particularly, the present invention relates to a wheelchair that may be folded and partially disassembled to allow for convenient options in storage and space for transporting in a vehicle. 
     BACKGROUND OF THE INVENTION 
     Folded wheelchairs for disabled persons are well known in the art. Generally, folding wheelchairs are folded along a vertical axis that brings together the wheels of the chairs. With a canvas seat and a canvas back, such chairs may be readily and quickly unfolded to be placed into service. 
     While such folded wheelchairs have the advantage of quick assembly, they suffer from the disadvantage of bulk. Folding such a chair overcomes the width of the chair as a dimension across a front elevation of the chair, but does not overcome the height of the chair in the same elevation or the depth of the chair. Thus, there is still considerable bulk with regard to the overall volume that the chair might occupy in a place of storage or in the trunk of a vehicle. Moreover, this bulk controls remaining storage space or luggage space, as conventional folded wheelchairs are not adapted for easy disassembly so that parts of the wheelchair may be stored in convenient recesses to maximize storage space for other articles. 
     OBJECTS OF THE INVENTION 
     With the above-described difficulties accompanying most known folding wheelchairs in view, a primary object of the present invention is to provide a folding wheelchair that has an axis for folding which allows for a more advantageous profile for storing and transporting the folded wheelchair. 
     Another object of the present invention is to provide a folded wheelchair that has means for disassembling part of the wheelchair to take advantage of arranging storage of the wheelchair with storage of other articles in a limited storage space. These and other objects have been achieved by the present invention. 
     SUMMARY OF THE INVENTION 
     A folding wheelchair includes a pair of spaced apart posts with pivotally connected side rails. A front leg is pivotally connected to the side rail. A side tensional support structure is pivotally connected to each leg and extends rearwardly to the post. The side rails may be pivoted toward a top end of the posts to fold the wheel chair. A pair of front wheels are attached to the front legs, and a pair of quick release rear wheels are connected to the pairs of posts. Cross members provide seat and back structure to support a person seated in the wheelchair and to join or interconnect the spaced apart side frames and posts. 
     The above-noted objectives and other advantages of the present invention will become more apparent to those skilled in the art as the invention is further explained in the accompanying detailed description and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment folding wheelchair according to the present invention with the pedal rest placed in a lower position. 
     FIG. 2 is a perspective view similar to that of FIG. 1 illustrating the release of the upper side rails from the side rails and the pivotal positioning of the armrests. 
     FIG. 3 is a view substantially similar to that of FIG. 2 illustrating a completion of folding of the upper side rails towards the posts. 
     FIG. 4 is a view similar to that of FIG. 3 illustrating the initial folding of the wheelchair according to the present invention by moving a front end of the side rails towards an upper end of the posts. 
     FIG. 5 is a perspective view of the wheelchair according to the present invention with the chair being fully folded to its vertical position with the rear wheels being removed. 
     FIG. 6 is an enlarged cut-away view of a portion of the folding wheelchair shown in FIG. 1 illustrating the pivotal connection of the side rail with the post and a rotative connection of the rear wheel with the post. 
     FIG. 7 is an enlarged cut-away perspective view of the wheelchair shown in FIG. 1 illustrating the pivotal connection of the post with a side tensional support member and illustrating the connection of the post with a pin mount for the rear wheel. 
     FIG. 8 is a view similar to that of FIG. 7 showing quick release pin and rear wheel being connected with the post. 
     FIG. 9 is an exploded view of the quick release pin, quick release pin spring, wheel hub, pin mount and post according to the present invention. 
     FIG. 10 is a view similar to that of FIG. 9 showing the quick release pin, quick release pin spring, a thrust bearing and the pin mount assembly. 
     FIG. 11 is a perspective view of a front corner end of the wheelchair shown in FIG. 1 illustrating the removable connection between the upper side rails and the side rail. 
     FIGS. 12A and 12B are sectional views illustrating the connection of the upper side rail with the side rail. 
     FIG. 13 is a sectional view illustrating the pivotal connection between the upper side rail and the armrest and the pivotal connection of the upper side rail with the post. 
     FIG. 14 is a sectional view of the armrest shown in FIG. 13 illustrating the armrest in the upright, normal operational position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1,  2  and  6 , a folding wheelchair  7  according to the present invention has two posts  20 . Each post  20  has a lower end  22  and an upper end  24 . Post upper end  24  has a perpendicularly bent portion  26 . Perpendicular portion  26  is encircled by a polymeric handle grip  28 . The primary shape of posts  20  is generally arcuate having its bowed section orientated forwardly. The two posts  20  are generally parallel spaced from one another. Posts  20  are fabricated from a tubular steel or other suitable material. Joining posts  20  together is a lower post cross rail  30 , mid-post cross rail  32 , and an upper post cross rail  34 . Mid-post cross rail  32  and upper post cross rail  34  form a back structure which extends between posts  20 . Typically, a back cushion (removed from the drawing for clarity of illustration) covers post cross rails  34  and  32 . As will also be apparent to those skilled in the art, post cross rails  30 ,  32  and  34  may be bowed as desired. 
     Extending forwardly from each respective post  20  is a side rail  40 . Side rail  40  has a front end  42  and a rear end  44  (FIG.  6 ). Side rail  40  is fabricated from a rectangular, tubular, steel member having its major dimension in the vertical orientation. The two side rails  40  are generally parallel spaced from one another. Posts  20  have a welded forwardly projecting outboard bracket  46 . Side rail  40  has a vertically oriented welded inboard bracket  48 . A pivot pin  50  extends through apertures in brackets  46  and  48  thereby pivotally connecting side rail  40  to its respective post  20 . Pivot pin  50  has a head (not shown) which abuts against bracket  46  and has a generally smooth shaft except an extreme end which is threadably joined to a nut which abuts bracket  48 . In the upright position a rear surface  54  of side rail  40  either directly or through an elastomeric cushion (now shown) makes abutting contact against post  20 . Connecting the two side rails  40  are a series of cross rails. A rearward most cross rail  58  joins the two side rails  40  at their rearward ends. Mid-cross rails  60  and  62  join side rails  40  between their forward and rearward ends  42  and  44 . At a forward end, the side rails  40  are joined by a cross rail  64 . Cross rails  62  and  60  connect with side rails  40  along a lower edge of the side rails  40 . Cross rails  64  connects with the side rails  40  along a position more adjacent with a vertical mid-point of the side rails  40 . Rear cross rail  58  is joined to the side rail  40  underneath but also has a wing  68  and a diagonal member  70  (FIG.  6 ). Cross rails  58 ,  60 ,  62  and  64 , along with side rails  40  provide a seat structure for supporting a person thereon and also provide a nest for a seat pad (not shown). Attached to the outboard side of each side rail  40  is a wheel brake  72 . The wheel brake has a handle  74  which can be manipulated to project a brake arm  76  (FIG. 3) towards the tires  80  of the wheel  82 . Fixably joined to the underside of the side link  40  adjacent their front ends  42  is a downwardly projecting welded bracket  86  (FIG.  11 ). 
     Folding wheelchair  7  has two front legs  88  to support the front end of the wheelchair  7 . Each front leg  88  is fabricated from a tubular steel material. Each front leg  88  has a slot  92  which receives bracket  86  of the side rail  40 . A pivot pin having a head  94  pivotally connects the side rails  40  with the front leg  88 . Front legs  88  have a lower end  96 . Front leg lower end  96  rotatively mounts along an axis inclined with the vertical axis of front wheel fork  98 . Front wheel fork  98  rotatively connects a front wheel  100 . Extending between and connecting with the lower end  96  of the front legs is a lower cross rail  102 . Cross rail  102  has connected thereto two downwardly extending subposts  104 . Subposts  104  support an occupant footrest or pedal  106 . In a method that is well known in the art, the angular position of pedal  106  can be adjusted with respect to the subposts  104  to thereby maximize occupant comfort. To provide added strength and stability, a leg cross post  108  is provided between the front legs. 
     Front legs  88  have a horizontally projecting stud  110  (FIG.  11 ). The stud  110  has pivotally connected thereto a side tensional support member  112 . Side tensional member  112  has a front end  114 . Front end  114  is pivotally connected to stud  110  via pivot pin  116 . A rearward end  118  of the side tensional support member  112  is pivotally mounted with respect to post  20  (FIG. 7) by a pin  120 . Pin  120  extends through an aperture in a bracket  122 . Bracket  122  is fixably welded to the post  20 . 
     Rear wheel  82  has a series of spokes  130  (FIG.  3 ). Spokes  130  support a rim  132  from a hub  134 . Referring additionally to FIGS. 8 through 10. Posts  20  have weldably connected rearwardly thereto a quick removable pin housing or mount  135 . A quick release pin  136  has a handle  138 . Handle  138  has fixably connected thereto a shoulder  140 . Projecting from shoulder  140  is an elongated shaft  142  having spring loaded retention balls  144 . A coil spring  148  encircles shaft  142  and is seated against shoulder  140 . To install a rear wheel  82  to the folding wheelchair  7 , shaft  142  of the quick release pin  136  is inserted into coil spring  148 . The remainder of shaft  142  is then inserted into wheel hub  134  and is inserted through the pin mount  135  until the retainer balls  144  re-emerge on the extreme inboard side of the pin mount  135 . Before insertion through the pin mount  135  the pin shaft  142  is passed through a thrust bearing member or washer  150  (shown only in FIG.  10 ). 
     To remove rear wheel  82  from the folding wheelchair  7 , quick release pin  136  is simply grabbed by its handle and pulled with such a force that retention balls  144  are urged inwardly to allow the quick release pin  136  to pass through the pin mount  135 . Quick release pin  136  will usually, for convenience purposes, be left within hub  134  when rear wheel  82  is removed by the seat occupant or an assisting party. 
     Referring additionally to FIGS. 12A through 13, the folding wheelchair  7  of the present invention has a transversely or inwardly pivoting upper side rail assembly  160 . The upper side rail  160  has two members  162  and  164 . Members  162  and  164  are both pivotally connected with the posts  20  via pivot collars  166  and  168 , respectively. Pivot collars  166  and  168  pivot along the axis generally perpendicular to the axis of pivotal movement of side rail  40  with respect to posts  20 . Upper side rail member  164  arcs vertically downward and is removably connected with side rail  40 . Side rail  40  along its upper end has a nest  170  to limit the outboard movement of the upper side rail  160 . On top of side rail  40  within nest  170  is an aperture  172 . A spring  179  loaded pin  174  within member  164  has a locator  176  which can be aligned with aperture  172  of the side rail. After alignment is achieved, the spring loading upon the pin  174  locks the upper side rail  160  with the side rail  40 . To remove upper side rail  160  from side rail  40  to allow it to be pivoted towards the seat back, there is provided a release handle  178  which allows locator  176  to be urged upwards against the force of spring  179 . The upper member  164  has pivotally attached thereto an armrest  180 . Armrest  180  has a metal base  182  joined to a cushion  184  by rivets  186 . Base  182  is joined to two collars  188  and  190 . Collars  188  and  190  allow armrest  180  to be pivoted to an outboard normal use position as shown in FIG. 1 or to be pivoted to its downward position as shown in FIGS. 2 and 13. 
     In operation the wheelchair  7  is mainly utilized in the position shown in FIG.  1 . When it is desired to fold the wheelchair  7  upper side rails  160  are released by an upward pull on release handle  178 . Armrest  180  is pivoted downward and as shown in FIG. 2 the two upper side rails  160  are folded towards posts  20 . Foot pedal  106  is pivoted upward to the position shown in FIG.  2 . Referring to FIG. 3, wheel foot brake  72  is activated. The side rails front end  42  are then pivoted towards post upper ends  24 . Rear wheel brakes  72  will naturally pull away from the rear wheel tire  80 . As shown in FIG. 5, the front wheels  100  will pivot to make an even thinner profile of the folding wheelchair  7 . Side structure support members  114  will also pivot causing front legs  88  to be pivoted towards side rails  40 . Quick release pins  136  will be pulled outward causing shaft  142  of the pin  136  to be removed from pin mount  135 . The wheelchair  7  can now be carried by its handles  26  and typically will be thin enough to be stored in a back seat of a vehicle. In many occasions the folding wheelchair  7  can be passed into a back seat of a two-door vehicle with a folding front seat because of the folded wheelchair&#39;s thin profile. Depending upon design considerations the seat cushions and seat back may be retained or removed from the wheelchair  7 . Therefore, the seat cushion or seat back may have a hard rigid backing that cannot bend. Assembly of the wheelchair  7  can be achieved in generally in a reversal of the steps mentioned. However, if desired, the wheelchair  7  can be assembled with the last assembly step being the attaching of the rear wheels  82 . 
     Although the present invention has been described with reference to a preferred embodiment thereof, it will be apparent to those skilled in the art that various alternatives and modifications can be carried out without departing from the scope of the present invention.