Portable wheelchair

A portable wheelchair including a seat assembly having a seat and a back rest, as well as a footrest having at least one guiding wheel. The seat assembly and the footrest are selectively secured between a first wheel and a second wheel, the first wheel including a first tire mounted on a first rim and the second wheel including a second tire mounted on a second rim. The seat assembly is secured to the first wheel by a first cross-brace and the seat assembly is secured to the second wheel by a second cross-brace. The first cross brace is coupled to the first wheel by a first bearing assembly slidably mounted to the first rim and a second bearing assembly slidably mounted to the first rim, wherein the first bearing assembly and the second bearing assembly are connected by a first spoke member. The second cross brace is coupled to the second wheel by a first bearing assembly slidably mounted to the second rim and a second bearing assembly slidably mounted to the second rim, wherein the first bearing assembly and the second bearing assembly are connected by a second spoke member.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a wheelchairs. More particularly, the invention 
relates to portable wheelchairs adapted for simple assembly and 
disassembly. 
2. Description of the Prior Art 
Conventional wheelchairs generally include a seat, a backrest, and a 
footrest rigidly secured to a pair of wheels. These wheelchairs are 
collapsed by pushing the wheels toward each other while the seat, 
backrest, and footrest collapse to the extent they are able to. As is well 
known to individuals familiar with these wheelchairs, they are generally, 
very cumbersome to transport or store, even when they are in their 
collapsed state. 
Recent advances in design techniques and materials has made the development 
of lightweight, portable wheelchairs possible. The recent development of 
lightweight, portable wheelchairs has been met with great anticipation by 
individuals confined to wheelchairs, who had to previously deal with the 
limitations of heavier, more cumbersome wheelchairs. 
However, recent developments in lightweight wheelchairs have produced 
relatively complex wheelchairs, which are not as easy to use as most 
individuals would like. For example, U.S. Pat. No. 5,261,684, to Soto, 
discloses a portable, lightweight wheelchair. The wheelchair includes a 
seat and footrest secured between a pair of spokeless wheels. The 
wheelchair is stored by disassembling the wheels, seat and footrest. The 
disassembly and assembly process is, however, complicated, and relies upon 
a variety of complex connections to retain the wheelchair in its assembled 
configuration. 
Consequently a need continues to exist for a lightweight, portable 
wheelchair that may be readily assembled and disassembled. The present 
invention provides such a wheelchair. 
SUMMARY OF THE INVENTION 
It is, therefore, an object of the present invention to provide a portable 
wheelchair including a seat assembly having a seat and a back rest, as 
well as a footrest having at least one guiding wheel. The seat assembly 
and the footrest are selectively secured between a first wheel and a 
second wheel, the first wheel including a first tire mounted on a first 
rim and the second wheel including a second tire mounted on a second rim. 
The seat assembly is secured to the first wheel by a first cross-brace and 
the seat assembly is secured to the second wheel by a second cross-brace. 
The first cross brace is coupled to the first wheel by a first bearing 
slidably mounted to the first rim and a second bearing slidably mounted to 
the first rim, and the first bearing and the second bearing are connected 
by a first spoke member. The second cross brace is coupled to the second 
wheel by a first bearing slidably mounted to the second rim and a second 
bearing slidably mounted to the second rim, and the first bearing and the 
second bearing are connected by a second spoke member. 
Other objects and advantages of the present invention will become apparent 
from the following detailed description when viewed in conjunction with 
the accompanying drawings, which set forth certain embodiments of the 
invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The detailed embodiment of the present invention is disclosed herein. It 
should be understood, however, that the disclosed embodiment is merely 
exemplary of the invention, which may be embodied in various forms. 
Therefore, the details disclosed herein are not to be interpreted as 
limited, but merely as the basis for the claims and as a basis for 
teaching one skilled in the art how to make and/or use the invention. 
With reference to FIG. 1, a portable wheelchair 10 is disclosed. The 
wheelchair includes a seat assembly 12 and a footrest assembly 14 
positioned between a first wheel 16 and a second wheel 18. Each wheel 
includes a tire 20 mounted on a spokeless rim 22. The rim 20 includes an 
outer groove 24 designed to retain the bead of the tire 18 and an inner 
bearing surface 26. Each rim 22 may further include an opening (not shown) 
permitting inflation of the tire. A cross-brace 28, 30 is secured across 
each wheel. 
With regard to the first wheel 16, the first cross-brace 28 is coupled to 
the first wheel 16 and includes a first bearing assembly 32 slidably 
mounted to the first rim 22.sup.1 and a second bearing assembly 34 
slidably mounted to the opposite side of the first rim 22.sup.1, wherein 
the first bearing assembly 32 and the second bearing assembly 34 are 
connected by a first spoke member 36. Similarly, the second cross-brace 30 
is coupled to the second wheel 18 includes a first bearing assembly 38 
slidably mounted to the second rim 22.sup.11 and a second bearing assembly 
40 slidably mounted to the opposite side of the second rim 22.sup.11, 
wherein the first bearing assembly 38 and the second bearing assembly 40 
are connected by a second spoke member 42. 
The detailed construction of the first bearing assembly 32 of the first 
wheel 16 is shown in FIG. 2. It should be understood that all of the 
bearing assemblies are constructed the same, with the exception of spoke 
connection details that will be discussed below, and this disclosure of 
the first bearing assembly of the first wheel is applicable to the 
remaining bearing assemblies. The bearing assembly 32 is rectangular 
shaped and extends around a portion of the tire 20.sup.1 and the rim 
22.sup.1. The bearing assembly 32 includes first and second bearing pins 
44, 46 which extend toward the middle of the bearing assembly 32 and 
engage the bearing surface 26 of the rim 22.sup.1. The bearing assembly 32 
further includes a pair of bearing plates 48 positioned on the side walls 
50, 52 of the assembly. The bearing plates 50, 52 act to maintain the rim 
22.sup.1 within the center of the bearing assembly 32. 
As shown in FIG. 3, each spoke member is constructed from a pair of 
aluminum tubular members. It should be understood that FIG. 3 shows the 
first cross-brace 28 for the first wheel 16 in detail, however, the second 
cross-brace 30 for the second wheel 18 is identical in structure and 
function. The first and second tubular members 54, 56 are releasably 
attached to the first bearing assembly 32 and the second bearing assembly 
34 of the first wheel 16. 
Specifically, the first bearing assembly 32 includes first and second 
openings 58, 60 sized to respectively receive the upper ends of the first 
and second tubular members 54, 56, while the second bearing assembly 34 
includes first and second detents 62, 64 sized to fictionally receive the 
lower ends of the first and second tubular members 54, 56. In use, the 
upper ends of the first and second tubular members 54, 56 are respectively 
passed into the first and second openings 58, 60 of the first bearing 
assembly 32. The first and second tubular members 54, 56 are pushed 
sufficiently within the openings 58, 60 to permit the lower ends of the 
first and second tubular members 54, 56 above the first and second detents 
62, 64. The first and second detents 62, 64 are then respectively forced 
within the first and second tubular members 54, 56 until the first and 
second tubular member 54, 56 are frictionally held in position. 
With reference to FIG. 4, the first tubular member 66 of the second 
cross-brace 30 of the second wheel 18 includes a first projection 68 with 
a quick release compression fastener 70. Although not shown, the first 
cross-brace 28 includes a similar projection and quick release fastener 
secured to the first tubular member 54 of the first cross-brace 28. The 
quick release compression fasteners are preferably of the type commonly 
used to secure bicycle tires to the bicycle frame, although other 
fasteners could be used without departing from the spirit of the present 
invention. The projections are used to securely attach the seat assembly 
between the wheels in a manner that will be discussed in more detail 
below. 
The seat assembly 12 is releasably coupled between the first and second 
wheels 16, 18. With reference to FIG. 4, the attachment of the second 
cross-brace 30 to the seat assembly 12 is disclosed. It should be 
understood that the first cross-brace 28 is secured to the seat assembly 
12 in the same manner. The seat assembly 12 includes a pair of downwardly 
extending brackets 72 (only the bracket adjacent the second cross-brace is 
shown) secured to the bottom of the seat 74. The bracket 72 includes an 
opening 76 sized to receive the first projection 68. Once the first 
projection 68 is properly positioned within the first bracket opening 76 
the quick release pressure fastener 70 is twisted to securely attach the 
seat assembly 12 to the second wheel 18. The first wheel 16 is attached in 
the same manner. 
The stability of the seat assembly 12 attachment to the first and second 
wheels is further enhanced by first and second support members 78, 80 
which extend from the bottom of the seat 74. Specifically, the first 
support member 78 is pivotally secured to one side of the seat 74 while 
the second support member 80 is pivotally secured to the other side of the 
seat 74. The unattached ends of the first and second support members 78, 
80 respectively engage notches (not shown) in the cross-braces 28, 30 to 
support the seat assembly 12 relative to the first and second wheels 16, 
18. 
As to the structure of the seat assembly 12, it includes a seat 74 and a 
backrest 82. Preferably, the seat 74 and the backrest 82 are hingedly 
connected so that the seat assembly 12 can be folded into a compact 
package when the wheelchair 10 is disassembled. The backrest 82 includes a 
pair of armrests 84, 86 on opposite sides of the backrest 82. The armrests 
84, 86 are pivotally secure to the backrest 82 and may be selectively 
folded down when an individual desires. The operation of the armrests 84, 
86 is shown in greater detail in FIG. 5. Specifically, the upper end 88 of 
each armrest is pivotally secured to the backrest 82. Each armrest 
includes a support bracket 90 pivotally mounted at a central portion on 
the underside 92 of the armrest, while the backrest 82 includes a series 
of notches 94 adapted to receive the unattached end 94 of the support 
bracket 90. When an individual desires to place the armrest in a useable 
orientation, he or she simply rotates the armrest upward and places the 
unattached end 96 of the support bracket 90 within a notch 94. The support 
bracket 90 includes a spring 98 secured at its distal end. The spring 98 
aids in securely positioning the distal end of the support bracket 98 
within a notch. This provides a well supported armrest that can readily be 
rotated to a storage position when an individual desires. 
The backrest 82 also supports first and second push handles 100, 102. The 
push handles are secured to opposite side of the backrest 82. The push 
handles are secured to the backrest so that they are fully retractable. 
With reference to FIG. 6, the push handles 100, 102 are stored within 
openings 104 formed in the backrest 82 of the seat assembly 12. When an 
individual desires to retract the push handles 100, 102 for use, he or she 
simply pulls the push handles 100, 102 from within the openings 104. Once 
the push handles 100, 102 are properly withdrawn, they are rotated such 
that detents 106 move from alignment with slots 108 respectively 
positioned adjacent the openings 104. Similarly, the push handles 100, 102 
are pushed back within the openings 104 by rotating the handles until the 
detents 106 are aligned with the slots 108. Once the detents 106 are 
aligned with the slots 108, the push handles 100, 102 will readily slide 
within the openings. 
The footrest assembly 14 is shown in FIG. 7, and includes a U-shaped 
support member 110 having a pair of arms 112, 114 connected by a central 
portion 116. Guide wheels 118 are respectively secured adjacent the distal 
ends of the arms 112, 114. The guide wheels 118 are conventional caster 
wheels and are designed to permit a wide range of motion. Additionally, a 
footpad 120 is secured to the distal ends of the arms 112, 114 in a manner 
that will be discussed in greater detail. 
As shown in FIG. 7, each arm includes an opening used for attaching the 
footrest assembly 14 to the first wheel 16 and the second wheel 18 in a 
manner that will be discussed in greater detail below. The footrest 14 
includes a first hinge 122 located where the first arm 112 meets the 
central portion 116 and a second hinge 124 where the second arm 114 meets 
the central portion 116. The first hinge 122 is designed to permit the 
first arm 112 to rotate counter clockwise when viewed from above and the 
second hinge 124 is designed to permit the second arm 114 to rotate 
clockwise when viewed from above. The arrangement of the hinges permits 
the footrest 14 to be folded in the most efficient manner. 
As mentioned above, a footpad 120 is secured to the distal end of the first 
and second arms 112, 114. As shown in FIG. 8, the footpad 120 is pivotally 
secured to the first arm 112 and releasably secured to the second arm 114. 
Consequently, the footpad 120 connects the distal ends of the arms 112, 
114 when the footrest 14 is in use, but permits the arms 112, 114 to be 
folded when the footrest 14 is no longer needed. Specifically, a hinge 126 
connects the footpad 120 to the first arm 112, while the distal end 128 of 
the footpad 126 includes a projection 129 which releasably engages an 
opening 130 in the distal end of the second arm 114. 
The footrest assembly 14 is releasably connected to the second bearing 
assembly 34 of the first wheel 16 and the second bearing assembly 40 of 
the second wheel 18 by respectively placing projections 132, 134 of the 
second bearing assemblies 34, 40 within the openings 136, 138 formed in 
the arms 112, 114 of the footrest assembly. The projections 132, 134 are 
placed within the openings 136, 138 before the pressure fasteners 70 are 
twisted to secure the seat assembly 12 to the first and second wheels 16, 
18. Consequently, when the pressure fasteners 70 are twisted to draw the 
first and second wheels 16, 18 securely toward the seat assembly 12, they 
also draw the projections 132, 134 securely within the openings 136, 138 
of the footrest assembly 14 to releasably attach the footrest assembly 14 
between the first and second wheels 16, 18. 
When a user determines that he or she is through using the wheelchair and 
desires to store it in a compact space, the user simply disengages the 
seat assembly from the first wheel and the second wheel by releasing the 
pressure fasteners. This also results in the removal of the footrest 
assembly from between the first and second wheels. Once the seat assembly 
is removed the push handle are placed in their stored position within the 
openings found in the backrest, and the backrest and seat are folded 
toward each other. Similarly, the footrest assembly is folded along the 
first and second hinges. The spokes may also be detached. Once everything 
is disassembled the seat assembly, footrest assembly, and spokes may be 
positioned within the wheel openings for compact storage of the 
wheelchair. The disassembly steps are simply reversed when an individual 
once again requires the use of the wheelchair. 
With the exception of the aluminum tubular members, the tires and the rims, 
all of the components of the present can be manufactured from high 
strength, lightweight plastic. As a result, the present wheelchair is 
fully portable and weighs only approximately 14 pounds. It should, 
however, be understood that are wide range of materials could be used 
without departing from the spirit of the present invention. 
While the preferred embodiment has been shown and described, it will be 
understood that there is no intent to limit the invention by such 
disclosure, but rather, is intended to cover all modifications and 
alternate constructions falling within the spirit and scope of the 
invention as defined in the appended claims.