Patent Publication Number: US-9408762-B1

Title: Drive system for a wheelchair

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. Ser. No. 14/261,343 filed Apr. 24, 2014, which is a continuation of U.S. Ser. No. 14/151,631 filed Jan. 9, 2014, a continuation of U.S. Ser. No. 14/029,138 filed Sep. 17, 2013, a continuation of U.S. Ser. No. 13/134,888 filed Jun. 20, 2011, a continuation in part of U.S. Ser. No. 12/315,548 filed Dec. 4, 2008, which claims the benefit of Provisional Patent Application No. 61/005,439 filed Dec. 5, 2007, Provisional Patent Application No. 61/005,446 filed Dec. 5, 2007, and Provisional Patent Application No. 61/005,447 filed Dec. 5, 2007. 
    
    
     FIELD AND BACKGROUND OF THE INVENTION 
     This invention relates to a wheelchair. Particularly, the invention is for a wheelchair which is propelled by means of a drive mechanism, the drive mechanism including a pair of reciprocating arm levers connected through a drive train to the rear wheels of the wheelchair. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, there is provided a wheelchair comprising: a frame or chassis; a seat mounted on the chassis; a front wheel assembly mounted on the chassis; a pair of rear wheels mounted on the chassis; and a drive train assembly for propelling the wheelchair in a selectively forward or reverse direction, the drive train assembly comprising an arm lever which can be moved back and forth by the user, a drive member connected to the arm lever by means of a chain, and a rear wheel hub assembly connected to the drive member by means of a chain. 
     The frame or chassis may be generally constructed of a plurality of block pieces connected to each other by a plurality of tubes. 
     In one embodiment, the seat comprises a base, a seating surface, and a back member, the back member being pivotable relative to the base so as to facilitate folding and storage thereof. The back member may comprise a pair of adjustable pads whose position and orientation can be adjusted to suit the physical requirements of the user. In one form, a circular lock slot may be positioned between the base and the back, the lock slot being adjustable between the folded and unfolded position, and a lock stop operation member at the top of the back member. 
     Preferably, the front wheel assembly is pivotable relative to the frame or chassis so that it is movable between a folded position for storage and transportation and an unfolded position for use of the wheelchair. The front wheel assembly may comprise a frame member, a foot support, a pair of castor modules, and wheels attachable to the castor modules. 
     In one embodiment, the arm lever has a lower portion connected to the chassis, a sprocket at or near the lower portion, and an upper portion which extends above the level of the seat so as to be conveniently located for gripping by the user. The arm lever may further comprise an inwardly directed handle at its end remote from the sprocket, and cables extending within the arm lever from the handle to the hub assembly. Preferably, the handles comprise rotatable gear changers, rotation of which acts on the cables to change gears formed in the wheel hub assembly. 
     In one embodiment, the rear wheel hub comprises a forward ramp ring and reverse ramp ring, and an inner clutch for selective operative engagement with either the forward ramp ring or the reverse ramp ring. An inner clutch slider may be provided upon which the inner clutch is mounted, the inner clutch slider having a slot therein for receiving a shift pull post, the shift pull post being axially movable by operation of a cable to shift the inner clutch slider within the rear wheel hub. Furthermore, a cable may extend between the shift pull post and the arm lever such that a user by maneuvering the arm lever is able to vary the tension in the cable to move the inner clutch slider and the inner clutch so as to selectively rotate each of the rear wheels in either a forward or rearward direction. 
     In a further embodiment, the rear wheel hub has associated therewith a sprocket which is connected by means of a chain to the drive member. The drive member may have a first sprocket and a second sprocket which connects by means of a chain to the sprocket on the arm lever, and a second sprocket which connects to the sprocket on the wheel hub by means of a chain. 
     Preferably, the drive member comprises a torsion mechanism having a torsion housing, a pair of sprockets at each end of the torsion housing, the torsion housing being rotatably mounted on a torsion shaft, the pair of sprockets at each end of the torsion housing being respectively connected to the arm lever and the rear hub respectively. 
     In one form, each of the rear wheels comprises a pair of wheel plates, the wheel plates being connected to the rear wheel hub assembly. The wheel plates may be substantially flat disk shaped structures which are spaced at an inner portion thereof at the connection to the rear wheel hub assembly and taper towards each other and are connected at an outer portion thereof where the tire mounts. 
     Preferably, the wheelchair further comprises a braking mechanism. The braking mechanism comprises a disk connected to the rear wheel hub assembly and a caliper attached to the swing arm and containing brake pads for selectively engaging the disk, the brake pads being operated by a brake engagement lever. 
     Furthermore, the seat may comprise a base, a seating surface and a back member, the seating surface being ergonomically configured for the comfort of the user. Each of the front wheels may comprise a pair of wheels. 
     In yet a further embodiment, the wheelchair comprises a pair of bolsters for supporting the legs of the user, each bolster comprising a plate like structure movable between a first position in which the legs of the user are supported and contained and a second position in which each bolster is moved to a non-operational position so as to be out of the way to facilitate the user in mounting or dismounting the wheelchair. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a top perspective view of a wheelchair in accordance with one aspect of the invention; 
         FIG. 2  is a bottom perspective view of a wheelchair in accordance with the invention; 
         FIG. 3  is a side view detail of the drive and torsion mechanism of the invention; 
         FIG. 4  is a perspective view of the hub and other components, and the brake disk of a wheelchair of the invention; 
         FIG. 5  is a perspective cross-sections through a gear hub in accordance with one aspect of the invention; 
         FIG. 6  is an exploded view showing various components and fittings of the gear and hub of the invention; 
         FIG. 7  is a perspective view of a gear and hub in accordance with the invention; 
         FIG. 8  is a perspective view showing a rear wheel, hub, and other components, as well as a part of the frame; 
         FIG. 9  is a cross-section through the rear wheel and hub and showing the gear mechanism; 
         FIG. 10  is a further cross-sectional perspective view of the rear wheel and hub of the type shown in  FIG. 9  of the drawings; 
         FIG. 11  shows a detail of the frame, arm lever, drive train and torsion bar of the invention; 
         FIG. 12  is a perspective view of a shaft collar and torsion bar which may be used in accordance with the invention; 
         FIG. 13  is a cross-section through the shaft collar as illustrated in  FIG. 12  of the drawings; 
         FIG. 14  is an exploded view showing the various parts and components which make up the shaft collar and torsion bar in accordance with the invention; 
         FIG. 15  is a detail view showing the shaft collar in relation to the frame and rear wheel; 
         FIG. 16  is a detail of the shaft, torsion bar, swing arm and folding joint area of the invention including a cover; 
         FIG. 17  is a further detail view of the arm lever, frame, drive and other components in accordance with the invention; 
         FIG. 18  is a perspective view of an arm lever of a wheelchair in accordance with the invention; 
         FIG. 19  is an exploded view of the upper portion of the arm lever showing some of the internal components; 
         FIG. 20  is a detail view showing the arm lever shaft and support area; 
         FIG. 21  is an exploded detail view of the arm lever pivot joint to facilitate folding of the handle on the arm lever; 
         FIG. 22  is a cross-section detail showing the pivot joint Of  FIG. 21  of the drawings, in the unlocked position; 
         FIG. 23  is a cross-section detail showing the pivot joint of  FIG. 21  of the drawings, in the locked position; 
         FIG. 24  is an exploded view of a part of the arm lever and the pivot joint; 
         FIG. 25  is a detail of the lever arm at the pivot joint illustrating the space; 
         FIG. 26  is a top perspective view of the front wheel assembly and platform of a wheelchair in accordance with one aspect of the invention; 
         FIG. 27  is a bottom perspective view of the front wheel assembly and platform; 
         FIG. 28  is a detail view of a pair of front wheels and suspension mechanism; 
         FIG. 29  is an exploded view of a front wheel assembly and suspension mechanism; 
         FIG. 30  shows a detail exploded view of the folding joint and part of the frame of a wheelchair in accordance with the invention; 
         FIG. 31  is a split view of the folding joint as shown in  FIG. 30  of the drawings; 
         FIG. 32  is a detail perspective view of the folding joint when in the folded position; 
         FIG. 33  is a perspective detail showing the wheelchair with the front wheel assembly in the folded position; 
         FIG. 34  is a perspective view of a seat for use on a wheelchair in accordance with the invention; 
         FIG. 35  is an exploded view of the seat showing the various parts and components thereof; 
         FIG. 36  is a detail view showing the back of the seat and the various mechanisms for adjustment thereof; 
         FIG. 37  is a perspective view of the parts and components relating to the seat to facilitate the unfolded and folded position of the seat; 
         FIG. 38  is an exploded view of the parts and components relating to the seat to facilitate the unfolded and folded position thereof as illustrated in  FIG. 37 ; 
         FIG. 39  is a perspective view of the seat back lower unlock handle system of a wheelchair of the invention; 
         FIG. 40  is an exploded perspective view of the seat lock mechanism for attaching the seat to the frame structure; 
         FIG. 41  is a detail of a component as illustrated in  FIG. 40  of the drawings; 
         FIG. 42  is a front view of a seat bolster for use with a wheelchair in accordance with the invention; 
         FIG. 43  is an exploded view of the seat bolster as illustrated in  FIG. 42  of the drawings; and 
         FIG. 44  is a split view of the seat bolster of the invention. 
     
    
    
     DESCRIPTION OF THE INVENTION AND DRAWINGS 
     With reference to the drawings, there is generally shown a wheelchair  10  (see  FIGS. 1 and 2 , and others) of the invention comprising a number of interrelated and cooperating parts and components. Generally, the wheelchair  10  comprises a chassis  12 , upon which is mounted a seat  14 . Also mounted on the chassis  12  is a front wheel assembly  16 , which may comprise one or two wheels. 
     A pair of rear wheels  18  are mounted on the chassis  12 , one on each side thereof. The wheels  18  are selectively driven by the user of the wheelchair  10  by means of back-and-forth movement of arm levers  22 , having a grip or handle at one end for holding by the user, and a sprocket at the other end. This sprocket is connectable to a torsion mechanism  24  by means of a chain, and the torsion mechanism  24  in turn connects to a hub and gears  30  in the rear wheel  18 . By selectively operating the gears which are within the hub  30  of the rear wheel  18 , as will be described below, the user of the wheelchair  10  can cause each of the rear wheels of the wheelchair  10  to be propelled in either a forward or reverse direction, or to turn the wheelchair, as the situation dictates. 
     The above represents an overall description of the essential components, and the description below, in conjunction with the numerous figures and illustrations, disclose details relating to each of these components, as well as their relationship and interaction. 
     Hub/Clutch 
     Reference is now made to  FIGS. 4, 5, 6, 7, 8, 9, 10  and others of the drawings which show details relating to the structure and function of the rear wheel hub  30 , including the clutch and gear change assembly housed therein. 
     The hub  30  of the rear wheel  18  is comprised of a housing which is formed by a clutch end cap  100  on the shift side, and a clutch end cap  104  on the sprocket side. The clutch sprocket  106  can be observed adjacent the clutch end cap  104 . Ramp rings  101  and  102  are located between the clutch end caps  100  and  104 . Each of the ramp rings  101  and  102  have pawl arm ramps  136 . The pawl arm ramps  136  formed on the ramp rings  101  and  102  have different or opposing directions. When the pawl arm ramps  136  on the ramp ring  102  are engaged with the pawl arms  122 , as will be described below, the wheelchair  10  will be propelled in a forward direction. Conversely, when the pawl arm ramps  136  on the ramp ring  101  are engaged, also to be described below, the wheelchair  10  will be propelled in a reverse direction. 
     A rear wheel collar  103  is attached to the ramp ring  101 , and a ramp ring collar  105  is provided outside and adjacent the clutch end cap  104 . The rear wheel collar  103  and the ramp ring collar  105  will be attached to the rear wheel  18 , as will be seen in other figures. The clutch sprocket  106  is mounted on a clutch sprocket mounting sleeve  107 . 
     An axle  108  extends through the hub, including the clutch end caps  100  and  104 , the ramp rings  101  and  102 , as well as the clutch sprocket mounting sleeve  107  and clutch sprocket  106 . Case bearings  118  and  119  are formed at each end of the hub in the clutch end caps  104  and  100  respectively. The axle  108  is held by and extends through these case bearings  118  and  119 , and is attached to the swing arm with fastening means utilizing the external threads at both ends. 
     Within the hub, there is an inner clutch slider  120 , including an internal slot  139  therein, the slot  139  receiving a shift pull post  113 . Appropriate maneuvering of a cable  145 , to be described, allows the shift pull post  113  to move axially within an axle slot  109  formed in the axle  108 , and the position of the shift pull post  113  within the internal slot  139  causes movement of the inner clutch slider  120 , causing hardware, as will be described, to move within the hub to allow selective engagement of either the ramp ring  101  or  102 , which results in the forward or reverse direction propulsion of the wheelchair, as mentioned above. 
     The inner clutch slider  120  includes a shoulder  144 , and a pair of inner clutches  121  formed on the inner clutch slider  120 . The inner clutches  121  includes three pawl arms  122  per inner clutch which engages the pawl arm ramps  136  in the ramp rings  101  and  102  respectively. The axial movement of the inner clutch slider  120 , as operated by the user, causes axial movement of the inner clutch  121 , thereby selectively engaging the pawl arm ramps  136  in ramp ring  101  and  102  respectively so as to effect forward or reverse motion of the wheelchair. 
     The axle  108  holds an axle sleeve  141 . The axle  108  has an axle through hole  138 . Further, the axle  108  comprises an axle flange stop  110  and axle flange shoulder  111 . The previously referenced axle slot  109 , through which the shift pull post  113  radially projects, is able to move axially within the axle slot  109 , extend into the internal slot  139  of the inner clutch slider  120 , and effect change of direction of movement of the chair. A shift shaft  112  is located and slides within the axle through hole  138 , and the shift pull post  113  threadedly attaches to the shift shaft  112  as shown. A shift spring  114  is provided to provide the biassing force on the shift shaft  112 , and is held in position by a spring retainer block  115 . 
     The shift shaft  112  and shift spring  114  are housed within the axle through hole  138  of the axle  108 . The shift pull post  113  extends outwardly through the axle slot  109 . A pair of clutch axle bushings  117  are provided, and an axle stop bushing  116  is provided between the axle flange stop  110  and one of the clutch axle bushings  117 . The axle sleeve  141  is then mounted over the clutch axle bushings  117  on the axle  108 . 
     The inner clutch slider  120  is then mounted over the axle sleeve  141 , and positioned such that the shift pull post  113  is received within the internal slot  139 . The case bearing  119  is positioned over the axle  108 , and the axle bearing  118  is positioned over the axle sleeve  141 , and the axle  108  passes therethrough. The hub with its various components as described above, and to which is attached to one of the rear wheels  18  of the wheelchair  10 , is capable of rotating about the axle  108 . 
     The inner slider clutch  120  comprises two inner clutches  121 , each of which has three pawl arms  122  mounted by means of a pawl post  122   a . One inner clutch  121  has pawl arms  122  which engage with the pawl arm ramps  136  on the ramp ring  101 , while the other inner clutch  121  has pawl arms  122  which engage with the pawl arm ramps  136  on the ramp ring  102 . These ramp rings  101  and  102  effect respectively forward or reverse direction of movement of the wheelchair when the arm levers are moved. The pawl arms are kept in tension by a collar spring. Only one of the inner clutches  121  will be in contact with pawl arm ramps  136  on the ramp rings  101  or  102  at any one time. The axial sliding of the inner clutch slider  120  between its first and second positions, corresponding to forward and reverse motion of the wheelchair, will cause either selective engagement with one such pawl arm ramp  136  or the other. The inner clutch  121  not driving a ramp ring  101  or  102  will be idle in the sense that it does not have any active driving capacity at this point. For an example of this, please see the figures which show the inner clutch  121  in contact with the ramp ring  102 , but not with the ramp ring  101 . 
     By means of an adjustable cable which forms part of the arm lever, and which will be described further below, the user of the wheelchair  10  causes the inner clutch slider  120  to move axially over the axle sleeve  141  and around the axle  108 . This is achieved by the axial movement of the shift pull post  113  engaging in the internal slot  139  of the inner clutch slider  120  and moving it so that an inner clutch  121  on the inner clutch slider  120  selectively engages the pawl arm ramps either on the ramp ring  101  or the ramp ring  102 . Since these respective ramp rings  101  and  102  have oppositely directed pawl arm ramps  136 , the movement of the arm lever will have opposite effects depending upon whether the inner clutch slider  120  is engaged with either one of these ramp rings  101  or  102 . Therefore, forward or reverse motion of the wheelchair can be achieved by operation of the cable and the selective positioning of the inner clutch slider  120  according to the direction of movement designed by the user. 
     Rear Wheel Arrangement 
     Reference is now made to the  FIGS. 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 , and others, which show the attachment of the rear wheel  18  to the gear and hub assembly  30 . These figures show the wheel plates  400 , and inner and outer plates fastened together around the perimeter via bolts  405  through holes  404 , and also connected to the hub  30  via bolts  406  though holes  403  in the rear wheel collar  103  and ramp ring plate  105 , thus connecting the wheel plates together and to the hub  30 . 
     Also shown is the wheel tire  401 , and a fender  402  which may be positioned thereover. The wheel and hub assembly is connected by means of a pair of swing arms  510 , including an inner swing arm and an outer swing arm respectively on the inside and the outside of the wheel and hub assembly via fasteners through the wheel collar mounting holes  124  into mounting holes  125  as well as via fasteners through small ramp ring plate mounting holes  130  into clutch end cap mounting holes  128 . As will be appreciated, the hub  30  contains the hardware mechanisms for driving the wheel, shifting gears, and achieving forward and reverse movement. 
     Also shown in these figures is a braking system including a disk and caliper arrangement, to be described further below. 
     Drive Train and Torsion Mechanism 
     The drive train torsion mechanism of the wheelchair propagation system will now be described, as illustrated in  FIGS. 3, 8, 11, 12, 13, 14, 15, 16, 17 , and others. The torsion mechanism  24 , as will be appreciated from previous description, comprises an intermediate structure between the clutch hub arrangement within the rear wheel  18 , as already described, and the arm lever  22 , particularly the sprocket thereof, of the wheelchair  10 . The torsion mechanism is thus connected to both the sprocket of the arm lever, on the one hand, and the clutch hub mechanism in the rear wheel, on the other, thereby facilitating the back-and-forth motion of the arm lever into driving energy for rotating the rear wheel  18 , in either the forward or reverse direction, through the hub clutch mechanism. 
     The torsion mechanism  24  comprises a torsion shaft  500  including a threaded through hole  504  and a splined end  528 . A torsion shaft bearing shoulder  515  surrounds a part of the torsion shaft  500 . A torsion outer housing  501  is provided, and includes a shoulder  506  on each side, and a series of slots  502  associated therewith upon which a sprocket  511  is received at mounted. The sprocket  511  has an opening  514  which fits over the end of the torsion outer housing  501 , and one or a series of sprocket mounting tabs  513  projecting into the opening  514  engage with corresponding or registering slots  502  on the torsion outer housing  501 . 
     A pair of bearings  505  fit over the torsion shaft  500  and support the torsion outer housing  501 . 
     Threaded end nuts are provided to secure the sprockets  511  onto the torsion bar outer housing  501 , and these threadedly engage with correspondingly threaded ends of the torsion outer housing  501 . 
     The torsion shaft  500  is received in and connected to the chassis portion of the wheelchair  10 , and is mounted within an outer main support  625  and an inner main support  626 , which are joined together by support tubes  628 . The torsion shaft  500  is supported within the outer main support  625  by means of a torsion bar bearing  633  and the splined end  528  is received within the fixed splined module  525 . The end of the torsion shaft  500  opposite that to the splined end  528  is received within the swing arm  510 , the other end of the swing arm  510  being connected to the axle of the rear wheel hub mechanism located in the center of the rear wheel  18 . 
     The torsion shaft  500  itself allows the rear wheel to have movement up and down much as cars have suspension. The torsion shaft  500  is mounted firmly at one end with splines  528  interlocked with splines  527  set inside a fixed module  525  and supported by bearings  633 . The swing arm  510  is fixed to the shaft  500  and utilizes its length to incur “twist” in the shaft  500 . The shaft  500  is preferably of a material that constantly returns to its original state and allows for the swing arm  510  and the rear wheel  18  to move fluidly as the wheelchair  10  may traverse terrain which may not be smooth. 
     Located about the shaft  500  is a torsion outer housing  501  which is free to spend in either direction and allows the arm lever motion to be transferred via chains and sprockets from an inboard line of motion to a more outboard line of motion, or transferred across the outer housing  501  which is rotating on bearings  505 , and supported by the torsion shaft  500 . In this way, the torsion shaft  500  is supporting two different actions, namely, motivation and suspension. 
     An arm lever  553  having a lower end is connected to an arm lever shaft  550 . The arm lever shaft  550  is supported by the arm shaft block  555 . The arm sprocket  551  is mounted over the arm lever shaft  550 , and has a plurality of teeth  552 . The arm sprocket  551  is connected by a chain to the first sprocket  511  on one side of the torsion outer housing  501 . The sprocket  511  on the other side of the torsion outer housing  501  is connected by a chain to the clutch sprocket  106 , details of which have been described above. 
     Arm Lever 
     As will be seen from the drawings, including  FIGS. 1, 2, 11, 16, 17, 18, 19, 20 , and others, the arm lever  553  extends upwardly from its mounted position on the arm level shaft  550 , and includes an access cover  558  around the main push handle body  557 . A push handle  565  extends transversely outwardly from the arm lever  553  so that it is inwardly directed with respect to the wheelchair  10  so as to provide easy access to the push handles  565  by the user. At the end of the push handle  565  there is formed a gear shift knob  566  which can be rotated by the user to change which inner clutch and pawl arms engage in the hub portion in the rear wheels, so that appropriate selection can be made to the forward and reverse motion of the wheelchair. Details as to how this may be achieved have already been described in detail above with reference to other figures and drawings. 
     Internal cable rollers  559  and  560  are provided, and rotation of the gear shift knob  566  alternatively tensions or slackens the cable which extend from the internal cable roller. This cable extends through a shift cable alignment groove  571 , and extend through the arm lever  553  and are appropriately directed to the gear and hub mounted in the wheel of the wheelchair. The rotation of the gear shift knob  566  therefore achieves, through the presence of the cables, the ability to effect movement of the inner clutch slider  120  to change gears, as described, to selectively achieve forward or reverse motion. 
     Handle Structure and Operation 
     Reference is now made to  FIGS. 18, 21, 22, 23, 24, 25 , and others, showing the handle structure and operation. This is one embodiment, and other versions or variations of this arrangement will also fall within the scope of the invention. The handle is positioned on the arm lever  553  for operation by the user, preferably extending inwardly from the arm lever  553 , and positioned in a convenient location for the comfort and easy operation of the user. 
     The handle is comprised of a pivot joint block  530 , and internal slider  533 , and an internal fixed locator  537 . A spring  532  is positioned between the pivot joint block  530  and the internal slider  533  so as to urge the internal slider  533  away from the pivot joint block  530  in the normal course. The pivot joint block  530  comprises a lock mounting extrusion  531  and a spring floor  530 A which forms a base or shoulder for one end of the spring  532 . 
     The internal slider  533  is a generally cylindrical structure having a shoulder stop  534  at one end thereof, and axial lock grooves  535  extending down its length on the outer surface thereof. A through hole  536  is provided for receiving various cables extending between the handle and the gear assembly so that the user can select forward movement, reverse movement, or a neutral position. The shoulder stop  534  forms the other surface for receiving the spring  532 . 
     The internal fixed locator  537  comprises four substantially equispaced pivot lock engagement tabs  538 , each of the tabs  538  being received in a corresponding lock groove  535  on the internal slider  533 . In one operating configuration, the engagement tabs  538  are received within the lock grooves  535  formed in the shoulder stop  534 , thereby preventing rotation of the internal slider  533  in this position. The internal fixed locator  537  further comprises a through hole  539  for the cables, as referenced above, and threads  537 A on the outer circumferential surface thereof. 
     A push handle main body  557  and the access cover  558  thereof are attached to the internal fixed locator  537 , and the pivot joint block  530  attaches to the arm lever  553 . A space  533 B is provided, and is of a size which is sufficiently large so that the axial movement of the handle toward the arm lever has the effect of sliding the internal slider  533  so that the engagement tabs  538  of the internal fixed locator  537  become disengaged from the lock grooves  535  in the shoulder stop  534 . The axial movement of the internal slider  533  is against the bias of the spring  532 , so that the spring  532  would in the normal course urge engagement between the tabs  538  and grooves  535  when they are suitably aligned. However, when the tabs  538  and grooves  535  are disengaged and nonaligned, the handle can be rotated up to about 90 degrees relative to the arm lever  553  allowing clearance when the chair is folded. In the folded position after a 90 degree rotation, the tabs  538  can re-engage in the grooves  535  to lock the handle in that configuration. 
     As mentioned above, the mechanism for rotating the handle as described above is just one of several which can be used in accordance with the invention, which is not limited to this specific configuration. 
     Front Wheel Assembly 
     The front wheel assembly  16 , as seen in  FIGS. 1, 2, 28, 29, 30, 31, 32, 33 , and others, is attached to the chassis  12  of the wheelchair  10  by means of a pair of forward down tubes  592 . The attachment of these forward down tubes  592  to the chassis  12  is achieved in such a way that the front wheel assembly  16  can be retracted, folded, under the chassis  12  so as to render the wheelchair in to a more compact and more easily transportable configuration. Further details relating to the mechanism for compacting or folding the front wheel assembly  16  will be provided below with reference to other figures. 
     Each of the forward down tubes  592  at their ends remote from the connection to the chassis  12  is attached to a caster module  355 . Extending inwardly and laterally from each caster module  355  is a frame joint  308 , attached to a substantially frame vertical tube  307 . A frame lower tube  306  connects each of the respective frame vertical tubes  307 , including frame joints  305  and a pair of frame pivot collars  304 . 
     A foot rest platform  300  is attached to the frame lower tube  306 , and includes foot rest vents  301 , ports  302 , a heel separator support  303 , a foot rest pivot tube  309 , and such other hardware that may be included for the users comfort and convenience. 
     Extending downwardly from each caster module  355  is a caster stem main body  362  which connects to the caster module  355  through a pair of caster module bearings  358  pressed into a caster module  355  at top and bottom openings. The caster stem main body  362  includes an upper caster stem  360 , having threads  361  for attachment through a securement of a caster module. The lower end of the caster stem main body has attached thereto a pair of front swing arms  366  mounted thereto by a pin or bolt extending through holes  367  and  365 . The front swing arms have apertures  368  therein for receiving the front axle  372 , which includes the front axle shoulder  373 . A pair of front wheels  353  each having their own front tire  354  is mounted on the front axle  372  at each end thereof, with appropriate additional hardware such as the front axle spacer  370 , front wheel bearing, and cap  377  to facilitate the connection. A spring  379  extends from the spring attachment notch  363  on the main stem body  362 , and the opposite end of the spring is received within the spring hole  369  on the front swing arms  366 . 
     As will be noted from the above construction, the attachment of the front wheels through the swing arm  366  and associated spring  379  provides a front suspension system for a smoother ride. The front wheels will be capable of some limited up and down rotational or pivotal movement, in response to encountered irregularities or bumps on the riding surface, against the bias of the spring  379 . The spring would return the wheels to their substantially normal position once the irregularity has been traversed. 
     The caster module  355  includes a headlight housing, which encloses the tip of the caster module  555 , and also contains a headlight port  326  and one or more headlights  327 . 
     Front Wheel and Foot Rest Folding Mechanism 
     As briefly alluded to above, the front wheels and frame assembly, as seen in  FIGS. 1, 2, 26, 27, 28, 29, 30, 31, 32 and 33 , and others, may be folded underneath the seat and chassis in order to compact or fold the wheelchair to thereby make it more convenient for storage and transportation. 
     As shown in the figures, a pivot lock module  575  attaches between the outer main supports  625  and  626  of the right side chassis. The pivot lock module  575  includes a series of pin and spring recess holes  589  for receiving a series of pins  579 . Pivot axle bolt holes  581  and  582  are formed in the outer main supports  625  and  626 , and a pivot lock module pull post rod  578  extends from the pivot lock pull post hat  577 , passing through the pivot axle bolt hole  581 , the hole  591 , and finally through the hole  592 . An extension  588  connects to the forward down tube  592  which is the main support for the front wheel assembly. Rotating and pivoting the tube  592  would of course result in the rotation, pivoting and folding of the front wheel assembly. 
     A pull cable limiting cup  584  is mounted about the pull post rod  578 , and has a shoulder  585 , as well as an alignment shoulder  586 . A pin lock release module  576  is provided having push legs  587 , and these act on the pins to push them into disengagement from the pin lock holes  580 . When the pins are in the pin lock holes  580 , rotation of the down tube  592  will be prevented. By pulling on the pivot lock pull post hat  577  and rod  578 , the pins by the action from the springs will be pushed out of the pin lock holes  580 , allowing rotation and folding or unfolding of the down tube  592 . The down tube  592  can be rotated from completely open (the usable position) to completely closed (the stored position) positions only. 
     Seat Structure 
     The wheelchair  10  comprises a seat  14  for accommodating the user. See  FIGS. 1, 2, 34, 35, 36, 37, 38, 39, 40 and 41  and others. The seat  14  is in many respects adjustable to suit the specific physical requirements of the user, so as to provide good comfort and positioning for propelling the wheelchair. Further, the seat  14  is configured with the arm lever so that the arm levers are in positions which may be best suited for grasping by the user and propelling the wheelchair. Further, the seat may include components and mechanisms which allow it to be folded and/or removed so as to make the wheelchair easier to store or transport by occupying a smaller footprint. 
     In one embodiment of the invention, there is shown a seat arrangement which includes a seat bottom  200  including a bolster mount pad  201 . An arrangement of lock seat joint  202 , including various openings  206  to make the seat lighter, are provided and the seat bottom  200  is appropriately mounted on the lock seat joint  202 . The structure may include mounting flat pads  204  for improved mounting and stability. 
     A pair of raiser arm pods  205  extend upwardly from the lock seat joint  202 . Each of the raiser arm pods  205  is connected to an upwardly extending steel tube  218  by means of a lower lock tube  215  and an upper lock tube  216 . The lower lock tube  215  connects to the raiser arm pods  205  through lock discs  208 , the lock discs  208  including axle mounting holes  211 , mounting holes  210 , as well as a pair of lock slots, one of the lock slots  209  being utilized when the seat is in the folded position and the other of the lock slot  209   a  be utilized when the seat is in the open or user position. 
     The pair of seat tubes  218  support a lower seat support pad  219  and an upper seat support pad  220 , which may be cushioned and are adjustably located on the seat tubes  218  to best meet the physical comforts and shape of the user&#39;s body. The adjustability of these seat support pads may not only allow the up-and-down movement thereof over the seat tubes  218 , but they may also be adjustable so that they can be moved backward and forward relative to the seat tubes  218  to meet the physical requirements of a specific user. They may also be adjustable in degrees, such as 90°, 117°, 62°, etc. (90° being generally vertical to the ground) to further meet the individual user&#39;s physical requirements. 
     The seat structure further comprises a pair of support or bolster arms near the forward end of the seat bottom  200 . These arms are designed for helping to keep the legs of the user confined and stabilized on the seat bottom, and may be maneuverable between a myriad of positions, for example from about 90° straight up moving 45° toward the center of the seat with each degree change making the bolster to seat relationship smaller and thus tighter for more confinement of thinner legs of a user. In a further position, the arms may be folded away or downwardly directed when not is use so as to make user access to the seat of the wheelchair easier when getting into or out of the seat. This will be described in further detail in a separate section below. 
     At the top of the seat tubes  218 , there is formed an operating mechanism in contact with the other structure on the chair, and by means of which the seats may be tilted and folded around the lock disk, enabling the seat back to move between its extended user position and the folded storage and transportation position. A seat lock module  234  is provided at the top of each seat tube  218  and a seat lock module insert  235  is provided and connected to a pull rod  236 , which slides through  235  via bushing  239 . A brace handle  232  is formed on the seat lock module. Also provided is a pull handle  233 . The pull handle  233  can be pulled outwardly or upwardly, and the brace handle  232 , being in a fixed position, may be used as a counterforce and grip to facilitate the folding and unfolding operation of the seat back. 
     The pull handle  233  connects to the pull rod  236  in the seat tube  218 . The pull rod  236  attaches to an unlock cable  241 , which at its other end attaches to a lock pull rod  217 . This comprises an upper lock tube  216  and a lower lock cube  215 . The lower lock tube  215  includes a seat lock block  243  which moves up and down in response to the pulling on the cable  241  within a seat lock block slot  244 . When the seat lock block  243  is in its lower or normal rest position, it is able engage within one of the lock slots  209  or  209   a . If the seat back has been tilted into its operating or unfolded position, the seat lock block  243  will be received within the lock slot  209   a . This will fasten the lock discs to the seat joint arm pods  205 , and secure the seat back in the generally operational position. When it is designed to fold the seat back, the pull handle  233  is raised, and through the action of the various components including the cable, the seat lock block  243  will slide upwardly in the seat lock block slot  244 , and out of the lock slot  209   a . The seat back is then free to rotate into the folded position, and when the folding has reached a sufficient degree, the lock slot block  243  will step into the lock slot  209  so as to keep the seat back in this folded position, until the user needs the wheelchair once more, and the seat back is unfolded by carrying out the generally reverse procedure described above. 
     A further figure of the seat release mechanism for unfolding and folding the seat back illustrates some of the additional components, including bushings and spread nuts. 
     In another embodiment, there is shown a seat lock block  250  including a seat lock block access port  251 , which operates in association with a seat lock mounting post  265  which has an engagement notch  266 . The seat lock mounting post  265  is received through a tapered opening  267  in the seat lock block  250  so that it can attach thereto. An access block  263  is received within the access port  251 , and a toggle arm  256  is attached between the seat lock block  250  and the access block  263  by means of a toggle arm axle  260 , one end of which is received in the axle mounting hole  252 , the other in an axle mounting hole within the access block  263 . A shoulder  261  on the toggle arm axle  260  is provided. Further, a toggle arm spring  255  provides the necessary force to keep the toggle arm  256  positioned. The mechanism further comprises a hole  254 , extending between the access port  251  and an access opening  268 , and allows the toggle arm  256  to engage the notch  266  in the seat lock mounting post  265 . The post is attached to the seat and the block is mounted to the frame structure. The post/seat is lowered into the hole in the block and the spring loaded arm lever is pushed out of the way until the post lowers significantly allowing the lever to reengage the notch in the post thus locking the post/seat in place. The lever is disengaged via a cable actuated by a lever. 
     When the seat mounting post is downwardly inserted into the seat lock block opening, a plurality of seat mounting blocks are securely attached to the seat support structure. A plurality of seat lock mounting posts are secure  265  are securely attached to the seat joint. 
     Seat Bolster Flap 
     As mentioned above, a seat bolster flap, as shown in  FIGS. 42, 43, 44  and others, is provided on each side of the seat to help contain or steady the legs of the user. The seat bolster flap  450  has one end thereof mounted in a groove  453  of a bolster flap base  451 , which is in turn mounted on a base plate  454  attached to the seat or other structure. A pin  456  passes through holes  455  in the base plate  454  and the holes  452  in the bottom flap base  451  so that these two components are connected to each other such that they can be selectively pivoted or rotated with respect to each other in order to move the seat bolster flap  450  between an upright position in which it contains the legs, and a retracted position to permit easy access for the user, and multiple selectable positions therebetween. 
     Two pairs of rosettes  457  are provided and are also mounted on the pin  456 . One pair is closest to the handle  465  and the other is further away. One half of each pair is mounted on the forward faces of the bolster flap base  451  while the other half of each pair is mounted to the back facing faces of the base plate  454 . The pin  456  runs through the center of all the rosette pieces. 
     One end of the pin threadedly engages in the hole  452 , while the other is treated threaded engaged with a plug  463 . The plug  463  cooperates with a handle  465  including an alignment slot  466 , and an arm spacer  459  is provided. It will be seen that the hole  467  in the handle  465  is not centered, but is in fact slightly off center. Therefore, as the handle  465  is rotated about the hole  467 , it will have the effect of pulling or pushing the pin  456  respectively, causing engagement or disengagement respectively between the rosettes surfaces. When loosened and somewhat disengaged, the seat bolster flap  450  can be more easily pivoted and rotated out of the way. When the user, on the other hand, has placed the seat bolster flap  450  in the desired position, the handle  465  can be rotated to act on the pen  456 , engage the various rosette surfaces, and prevent further rotation or pivoting of the seat bolster flap  450 , until a handle is once more adjusted according to the needs and desires of the wheelchair user. 
     The invention is not limited to the precise details relating to structure and operation as described above. Many different embodiments for within the scope of the invention. 
     Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and procedures disclosed or claimed. Although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments. 
     As used herein, “plurality” means two or more. As used herein, a “set” of items may include one or more of such items. As used herein, whether in the written description or the claims, the terms “comprising”, “including”, “carrying”, “having”, “containing”, “involving”, and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of”, respectively, are closed or semi-closed transitional phrases with respect to claims. Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. As used herein, “and/or” means that the listed items are alternatives, but the alternatives also include any combination of the listed items.