Adjustable frame wheelchair

A wheelchair having opposing sideframes which comprise individual frame sections which are connected by a longitudinally and angularly adjustable joint. The frame sections include a fixed base section connected to linear bar sections. The bar sections are provided with lateral slots containing slidable fasteners. Link elements having fasteners that engage the slidable fasteners join together the bar sections. The joint is movable along the bar section slots and is rotatable about the link fasteners. Similarly, adjunct wheelchair assemblies may all be adjustably connected to the slidable fasteners of selected frame bar sections. The sideframes can include side braces and may be connected by laterally adjustable spacer bars.

BACKGROUND OF THE INVENTION 
Special needs of wheelchair users dictate an unending variety of 
alterations to a basic wheelchair structure. Unfortunately, virtually all 
improvements for making a wheelchair more adaptable are limited to just 
one or two components. For example, U.S. Pat. Nos. 3,815,586 and 4,073,537 
describe universally adjustable body support pads. The pads are connected 
to a fixed non-adjustable wheelchair framework. U.S. Pat. No. 4,592,570 
describes a seat frame which is adjustably attached to a fixed main frame. 
The frame itself cannot be altered. U.S. Pat. No. 4,595,212 sets forth a 
fixed side frame having means for adjustable connection with wheel 
assemblies. Again, adjustment of the sideframe is not possible. 
Adding to the difficulty of providing adjustability to wheelchair 
components, is the desire to make the chair collapsible. This entails more 
complicated mechanisms, more cost and more weight. It severely limits the 
overall adaptability of present day wheelchairs. 
SUMMARY OF THE INVENTION 
A wheelchair is provided having a framework comprising opposing sideframe 
structures which can be geometrically varied as desired. The sideframes 
may be adjustably spaced-apart by a folding assembly. The sideframes 
comprise individual frame sections having track means that is utilized in 
forming a wide variety of structural and supplemental connections. Link 
and attachment means are used to adjustably interconnect the frame 
sections to create a stable lightweight framework.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to FIGS. 1-3 of the drawings, a comprehensive wheelchair 
design is shown incorporating the unique features of the present 
invention, The basic wheelchair framework comprises two generally parallel 
spaced-apart sideframes 12,14 which are usually configured to be 
mirror-images of each other. Although the sideframes may be fixed in a 
spaced-apart relationship by conventional cross-pieces (not shown), they 
are preferably movable by a folding assembly 16. 
With particular reference to FIGS. 12-14, each sideframe comprises a base 
section 20 and at least three discrete frame bar sections shown as upright 
section 21, upper section 22 and front section 23. The bar sections 
consist of linear structural elements preferably of lightweight extruded 
aluminum, aluminum alloy or composite plastic. Each section includes a 
track means which, as shown, comprises an undercut slot 24 extending 
laterally along at least one, and preferably two opposing bar section 
sides. 
Most conveniently, the slots extend throughout the length of the inner face 
38 and outer face 39 of each bar section. Each slot has a cross-sectional 
shape corresponding to the outline of a slidable fastener 23 which is 
retained therein. As best shown in FIGS. 4-8, the slots have a T-shaped 
cross-section and the slidable fasteners comprise a conventional nut 
having a threaded opening accessible through said slot. 
As will be hereinafter apparent, the number of slidable fasteners contained 
in each track means will be dictated by bar section connections and the 
requirements of supplemental engagement means. Further, it will be 
appreciated that track means may include slotted strips or sliding bolt 
means and the like, secured to one or more of the bar section faces. 
Base section 20 comprises an elongated part 28 secured to a transversely 
extending leg part 29. Each part has an outer end that includes attachment 
means for connection with a frame bar section. The attachment means 
comprises an outer bar opening 30 at the outer end of elongated part 28 
including upper opening 31 and lower opening 32 at the opposing ends of 
leg part 29. An end of a frame bar section is inserted into a selected 
opening and adjusted longitudinally as desired. End fasteners 33 extend 
transversely through the outer end walls and engage corresponding slidable 
fasteners 25 in the bar section slots to secure the bar sections in place. 
Preferably, the base section comprises straight hollow structural parts 
having quadrilateral cross-sections corresponding to, and slightly larger 
than, the quadrilateral cross-sectional shape of the frame bar sections. 
In this way, the bar sections can telescope into the base section openings 
and be readily adjusted longitudinally. It is also preferred to have leg 
part 29 extend about perpendicularly across the back end of the elongated 
part. In this manner, a fixed angular corner A will be formed to provide a 
strong foundation for the overall sideframe structure. 
In the FIGS. 1-12 embodiment of the sideframes, upright section 21 extends 
upwardly from opening 31 and a lower bar section 26 extends downwardly 
from the lower bar opening 32. The longitudinal axis of both sections and 
the leg part are coextensive forming a straight backside to the sideframe. 
Note that the upright and lower sections have identical cross-sectional 
shapes and, in fact, the lower section 26 may simply be a continuation of 
upright section 21 that extends through leg part 29. Be aware also that 
use of the lower section is optional and it functions primarily to secure 
the lower end of a brace means in a manner to be hereinafter described. 
Telescoping out from bar opening 30 is optional bottom frame bar section 
27. This bar section serves as a linearly adjustable extension of 
elongated part 28. Its construction is the same as the lower and front bar 
sections. It includes slots 24 and slidable fasteners 25 which serve to 
adjustably secure it to opening 30 with end fasteners 33. 
The outer end of the bottom section is joined to front section 23 by a 
tightenable link means 35. Although various types of H brackets, yoke 
bars, clamps and braces could be used for the link means, the preferred 
means is shown as connector elements 36 with link fasteners 37. The 
connector elements are flat generally rectangular plates having 
spaced-apart orifices through which the link fasteners extend. The link 
fasteners preferably comprise bolts which are threaded to engage the 
female threads of the slidable fasteners. Of course, other types of link 
fasteners could be used as dictated by the particular link means and track 
means being utilized such that the invention should not be limited by any 
specific fastening system. 
The link fastener orifices are arranged to include at least two at a 
securement end portion of each connector element and one at an opposing 
pivot end portion thereof. As so arranged, link fasteners extending 
through the securement end orifices into engagement with the respective 
slidable fasteners, wi-l serve mainly to firmly fix the element to the end 
of a bar section. However, the link fastener extending through the pivot 
end orifice into engagement with a slidable fastener on the adjacent 
connecting bar section, will function as a pivot until tightened. Thus, an 
angularly adjustable joint is formed between the connecting bar sections. 
Further, the joint will be longitudinally adjustable as a result of the 
slidable fastener on the adjacent bar section. Still further, the 
connector elements can be reversed for allowing either bar section to be 
pivotable. 
With reference back to the connection of bottom section 27 to front section 
23, a connector element is secured to the bottom section outer end with 
two securement end link fasteners 37. A pivot end fastener 37' extends 
through the pivot end orifice and engages a slide fastener from front 
section 23. Before the fasteners are tightened, the angle B between the 
bottom and front sections can be varied as desired. Also, the front 
section can be moved longitudinally relative to the bottom section outer 
end. Clearly, this allows for unlimited variety in size and geometric 
arrangement of each sideframe structure. Further, note that to strengthen 
the joints, the link means may be used, as shown, on both the inner and 
outer bar section faces. 
In a similar fashion, angular and longitudinal adjustable link fastener 
joints can be formed with upper section 22 at the upper ends of front 
section 23 and upright section 21. As shown, the securement portion of 
each connector element is secured to the bar section upper ends. The pivot 
link fasteners 37' engage respective slidable fasteners at opposing ends 
of the upper bar section. Angle C between the front and upper bar sections 
and angle D between the upright and upper bar sections can be varied in 
the same manner as angle B. All three angles will also vary in accordance 
with the desired spacing between joints on the upper section and front 
section and, per the amount the bottom section and upright sections extend 
from the base section parts. 
In the FIG. 13 embodiment, lower section 26 and bottom section 27 are 
omitted. The front section 23 is rotated inwardly forming an acute angle C 
and is attached to the elongated part 28. As shown, the securement portion 
of the connector elements are fixed to the outer end of part 28 and to the 
upper end of front section 23. This permits securement anywhere along the 
longitudinal extent of the front section. The sideframe configuration of 
FIG. 13 may be appropriate where leg support is not required or where 
obstructions at the wheelchair front must be minimized for desk or counter 
work. 
FIG. 14 illustrates the basic sideframe construction of FIG. 13 in an open 
configuration. Here, the front section inclines outwardly from its upper 
end forming an obtuse angle C without connection to elongated part 28. 
This embodiment provides an ultra lightweight structure suitable for use 
by children or in sport applications. 
It should be noted that upper bar sections 22 have a greater 
cross-sectional area than the front, bottom, upright and lower bar 
sections which, otherwise preferably have identical cross-sections. The 
increased area allows for the addition of a seat keyway 34 on inner faces 
38. The seat keyway extends throughout the length of the upper bar section 
and includes an enlarged inner area 84. The enlarged area provides a means 
for retaining the expanded side edges 87 of seat 85. 
With reference to FIGS. 5 and 6, seat 85 preferably comprises a durable 
pliable material that spans the area between opposing upper bar sections. 
A seat engagement means is provided whereby the material is folded 
180.degree. to form the opposing edges 87,87 and, retainer rods 86 are 
inserted between the folds to expand the edges. The edges are then guided 
simultaneously into respective open ends of the seat keyways on each upper 
bar section. Free ends of the edge folds (not shown) may be secured by 
hemming or be drawn together by lacing or the like. 
Since the seat material is pliable, such as with canvas, leather or 
reinforced Nylon fabric, it will flex and crease along its midportion when 
the sideframes are drawn together into a wheelchair closed position. It 
will be appreciated, however, that if the wheelchair is noncollapsing, a 
rigid seat with engagement edges could be used in place of the pliable 
seat material. 
For heavy duty wheelchair applications, it may be desirable to strengthen 
the sideframe structures with brace means 40 as shown in the FIGS. 1-12 
embodiment. The brace means may comprise an elongated member that connects 
upper section 22 with base section 20 or lower section 26. Most basically, 
it may simply consist of a shaft conventionally secured to the aforesaid 
sections. However, it is preferable that the brace means include means to 
accommodate the variable geometry of the sideframe. To this end, universal 
joint means are used to connect the brace to the frame sections at varying 
angular adjustments. Longitudinal adjustment means may also be used to 
vary the brace length and facilitate attachment along the length of a 
frame bar section. 
With particular reference to FIGS. 2, 3, 6, 8 and 11, the brace means 
includes an elongated hollow brace member 41 having opposing upper and 
lower open ends. The lower end is provided with a stationary plug 42 which 
is secured therein by pin 43. Attached to the outer end of the plug is a 
lower universal joint assembly 44. This includes a ball fastener 45 having 
a ball end and a shaft end which is threadably engaged to the plug end. 
Surrounding the ball end and forming a universal joint therewith is 
annular joint fastener 46. The joint fastener includes a threaded portion 
that extends through base section orifices and engages corresponding 
threads in a lower bar section slidable fastener. A set nut and washer 
assembly 47 inhibits loosening of the fasteners. 
The upper open end of brace member 41 contains longitudinal adjustment 
means which, as shown, comprises sliding shaft 50. The shaft includes 
orifices 51 that are axially spaced-apart and correspond to brace member 
orifices 52. A releasable pin 53 engages selected aligned orifices of the 
shaft and brace member in accordance with the desired axial extent of the 
plug (and overall brace length). 
In the same manner as with stationary plug 44, an upper universal joint 
assembly 54 is attached to the end of sliding shaft 50. The upper assembly 
includes a ball fastener 45 secured to the end of shaft 50. A joint 
fastener 46 forms a universal joint with the ball fastener. However, the 
threaded end of the joint fastener is secured to a joint block 56. The 
block facilitates a strong connection with upper section 22 and includes 
upper fasteners 57. The upper fasteners engage upper section slidable 
fasteners to secure the upper end of the brace means to the desired 
position along the upper section slot 24. 
In some wheelchair applications, it may be desirable to move the upper 
assembly forward. Alternately, the sideframe height or width may be 
increased which, in turn, alters the variable corner angles B, C and D. In 
all of the above cases, simple adjustment of the brace means length will 
be all that is needed for disposing the brace means in the most suitable 
alignment. This is because the universal joint connections permit 
automatic angular movement at the point of connection. Consequently, the 
sideframe of the invention is provided with an effective strengthening 
means which does not at all detract from the sideframe's ability to change 
configuration. 
The folding assembly 16 of the invention is most conveniently attached to 
opposing sideframes via the abovedescribed brace means. This eliminates 
additional multiple connections to the appropriate frame sections, saves 
cost, minimizes weight and prevents interference with sideframe 
adjustability. The assembly includes at least one pair of hinged spacer 
bars having lateral adjustment means for varying the distance between 
sideframes. 
With reference to FIGS. 1-3, 10 and 11, an illustrative folding assembly is 
shown comprising a pair of upper spacer bars 60,61 and lower spacer bars 
62,63. Each pair includes overlapping inner end portions having aligned 
openings through which a pivot shaft 64 extends. The shaft is secured by 
nut 65. The outer ends of each bar are secured to respective opposing 
brace members 41. The bar connections to each brace member preferably 
occur adjacent to the ends of the member. In this way, greater leverage 
occurs to pivot the assembly and move the sideframes in and out. Also, as 
a result of the bars being connected at spaced-apart locations on the 
brace member, a stronger more stable alignment occurs between the opposing 
sideframes. 
The pivot shaft openings 66 are located at the inner end of outer bars 
60,62 and at a location inwardly offset from the end of inner bars 61,63. 
The offset portions of the inner bars form locking arms 68. The arms swing 
beneath overlapping inner end portions of outer bars 60,62 when the bars 
are in straight alignment corresponding to a wheelchair open position. To 
secure the bars in straight alignment, the locking arms are provided with 
a lock pin 67 which is biased outwardly by spring 71 into corresponding 
lock openings 72 on the inner faces of outer bars 60,62. Lock ring 70 is 
pulled to withdraw the lock pin and permit the bars to pivot toward each 
other. This action results in the sideframes being drawn toward each other 
and disposes the wheelchair in a closed inoperative position. 
The folding assembly lateral adjustment means comprises corresponding 
openings 66 which are spaced-apart at predetermined locations along the 
length of each bar. The desired spacing between sideframes can thereby be 
varied by inserting pivot shaft 64 through openings aligned in 
correspondence to the desired spacing. In such case, the amount of bar 
overlap will vary accordingly. Therefore, equally spaced-apart lock 
openings will be required to allow entry of the lock pin to secure the 
bars in straight alignment. 
To enhance lateral stability of the wheelchair when in an open position, 
the folding assembly can include strut means to interconnect a spacer bar 
to an opposing sideframe. In FIGS. 1-3 and 10, crossing strut members 
75,76 are shown connecting upper spacer bars with respective sideframe 
base sections. Ball joint means are used for end connections to allow 
unrestricted angular movement of the strut members with the spacer bars. 
With particular reference to FIGS. 3, 10 and 11, the upper end of strut 
member 75 is connected to upper spacer bar 61 by upper ball joint means 
77. The ball joint means includes a round head and ball fastener 78 that 
threadably engages strut opening 79 of the spacer bar. Ball ring 80 
conformally engages the round head and includes a ring fastener 81 that 
extends axially by threaded engagement into the outer end of the strut 
member. 
The lower end of strut member 75 is shown as connected with the outer end 
of elongated part 28 on the sideframe which is opposite of spacer bar 61. 
If desired, the lower connection could be to the adjacent bottom section 
27. In the lower connection, the ball joint means is the same as in the 
upper connection. However, ball fastener 78 engages a strut block 82. The 
strut block, in turn, includes strut fasteners 83 which engage the 
slidable fasteners contained in bottom section 27. 
Use of the strut block provides a stronger connection and allows movement 
of the lower connection onto and along the bottom frame section. In this 
regard, the upper spacer bars include additional strut openings 79 and, 
the strut member length can be varied by rotation of the threaded ring 
fasteners. It will be further appreciated that all of the above discussion 
applies equally to strut member 76. The only exception is that the upper 
end of strut member 76 is attached to spacer bar 60 and the lower end is 
connected to part 28 on the sideframe opposite spacer bar 60. 
The wheelchair backrest means will now be described which demonstrates some 
of the unique advantages of the novel sideframe structure. The backrest 
means includes a pair of upstanding backrest frame bars 90,91 each joined 
to a respective upper bar section 22 by backrest link means. The 
cross-sectional shape of the backrest frame bars and upper bar sections 
are substantially identical. Therefore, the backrest link means can 
include connector elements 36 with link fasteners 37 and pivot end 
fasteners 37'. 
As best shown in FIGS. 1 and 2, connector elements 36 are positioned at 
opposing sides of the lower end of each backrest frame bar. Link fasteners 
37 engage corresponding slidable backrest fasteners contained within slots 
24 in the same manner as with the sideframe bar sections. The pivot 
portion of each connector element extends beyond the end of the backrest 
bar and overlies respective inner and outer faces of the upper bar 
section. Pivot link fasteners are then used to engage corresponding 
slidable backrest fasteners in the upper bar section slots. 
To strengthen the backrest joints, the backrest link means may include an 
angle bar 93. The upper end of each angle bar is positioned to overlie the 
upper end of an outer face connector element. It is then secured, along 
with the connector element by a link fastener common to both. The angle 
bar lower end includes a pivot fastener 37' that engages a corresponding 
slidable fastener in the upper bar section slot. With the above 
arrangement, it can be seen that the backrest bars may be readily moved 
longitudinally along the upper bar sections. They can also be tilted as 
desired to vary angle E with the upper section. 
To provide upper backrest support, a pair of hinged support arms 95,96 are 
used to interconnect with opposing upper portions of the backrest bars. 
The arms are hinged at inner ends by support pin 97. The arms include a 
lock means to releasably maintain an open collinear position. The lock 
means comprises hook 98 at an extended portion of arm 95 that engages a 
hook pin 99 projecting from arm 96 when the arms are in longitudinal 
alignment. 
The opposing outer end of each support arm is hinged to a respective arm 
block 101,102. Each block is provided with arm fasteners 103 that engage 
slidable backrest fasteners in the backrest bars. This connection allows 
adjustment and movement of the support arms up and down the backrest bars. 
In the same same way as with the upper bar section seat keyways, the 
backrest bars include backrest keyways 104. A back support structure 105, 
shown in phantom in FIGS. 1 and 3, includes enlarged opposing side edges 
which slide into the keyways at the open end of each backrest bar. The 
back support structure can be rigid as with a non-collapsing wheelchair, 
or it can be flexible such as with the seat material. 
Conventional wheelchair drive wheels 107 (depicted in phantom in FIGS. 1 
and 3) are secured to the elongated part 28 of respective opposing base 
sections. The extended axle 109 of each drive wheel extends through an 
opening 110 in axle plate 111 and is fixed thereto by axle nut 112. Plate 
fasteners 113, that extend through clamp plate 114 and threadably engage 
the axle plate, draw the plates against opposing sides of the elongated 
part. This clamping action secures the wheels in place. It also permits 
adjustment of wheel location anywhere along the length of the elongated 
part. 
To exemplify the advantages of the invention, it will be appreciated that 
attachment of adjunct wheelchair assemblies (such as footrests, casters, 
armrests, handles and body support pads), can all be accomplished with 
supplemental connector means in conjunction with the slidable fasteners of 
the novel frame bar sections. Use of the above, in cooperating relation 
with frame bar track means, allows all supplemental connections to be 
semi-permanent and adjustable. This feature together with the infinitely 
variable sideframe geometry, makes it possible for a single wheelchair to 
be adaptable for an endless variety of special needs and uses. 
To illustrate the above, note conventional caster assemblies 114 which are 
secured to the forward position of bottom bar section 27 by a caster block 
means. Such means provides a supplemental connector junction whereby a 
caster assembly is connected to caster blocks 115. The block, in turn, 
includes block fasteners 116 which engage slidable fasteners in the bottom 
bar section. The combined assembly can be moved, as desired, anywhere 
along lateral slot 24. 
Similarly, handles 118 are joined to the upper portion of respective 
backrest bars by supplemental means comprising a handle connector block 
119. The block is split to frictionally engage the tubular handle base. 
Threaded handle fasteners 120 tighten the block to the handle. The 
fasteners also engage corresponding slidable backrest fasteners in the 
backrest bars. 
In a similar fashion, supplemental connector means, shown as footrest block 
122 with fasteners 123, interconnect footrest plates 124 to slidable 
fasteners in front bar section 23. Even more simply, a toggle brake 
assembly 126 includes brake fasteners 127 which pivotably connect brake 
arms directly to the upper bar section via engagement with corresponding 
slidable fasteners. 
In a more detailed manner, armrests 130 are joined by a supplemental 
armrest mounting means to respective backrest bars 90,91. The mounting 
means includes a split block 131 securing a transverse shaft 132. The 
shaft rotatably supports the handle by engagement with housing 133 at the 
handle base. Peg 134 extends from the shaft into the slot and impinges the 
slot end to limit, in a predetermined manner, up and down rotation of the 
handle. The split block 131 includes armrest fasteners 135 which engage 
corresponding slidable backrest fasteners in the backrest bars. 
While the invention has been described with respect to preferred 
embodiments, it will be apparent to those skilled in the art that various 
modifications and improvements may be made without departing from the 
scope and spirit of the invention. Accordingly, it is to be understood 
that the invention is not to be limited by the specific illustrative 
embodiments, but only by the scope of the appended claims.