Wheel chair abstract
A collapsible portable manual wheel chair is converted to a collapsible
electric wheel chair. The two large rear wheels of the collapsible
manual wheel chair are removed, and an electromechanical drive unit
is substituted in their place. The drive unit includes a left drive
wheel assembly, a right drive wheel assembly, a battery mounting
assembly, and a control device supplying electric power to each
of the drive wheel assemblies for propelling and steering the wheel
chair. The left and right drive wheel assemblies and the battery
carrier assembly are each manually removable from the wheel chair
frame to permit collapsing the wheel chair frame and are each manually
removable from one another to provide portable light weight components.
Wheel chair claims
What is claimed is:
1. A collapsible portable electric wheel chair comprising a collapsible
frame, a collapsible seat on said frame, at least one front wheel
on said frame, and a drive unit, said drive unit including a first
drive wheel assembly, a second drive wheel assembly, means supplying
electric power to each of said drive wheel assemblies for propelling
and steering said wheel chair, first fastening means manually releasably
securing said first and second drive wheel assemblies to said frame
whereby said first and second drive wheel assemblies are manually
removable from said frame when said frame is to be collapsed, each
of said drive wheel assemblies including an electric motor and a
ground engaging drive wheel and means drivingly connecting said
electric motor and said ground engaging drive wheel, and second
fastening means manually releasably securing said first and second
drive wheel assemblies to one another whereby said first and second
drive wheel assemblies are manually separable from one another when
removed from said frame.
2. A collapsible portable electric wheel chair as set forth in
claim 1, wherein said drive unit includes an electric battery and
a battery carrier assembly, said battery carrier assembly is disposed
between said first and second drive wheel assemblies, and said second
fastening means includes said battery carrier assembly.
3. A collapsible portable electric wheel chair as set forth in
claim 2, wherein said battery carrier assembly and said battery
are disposed between said ground engaging drive wheels of said first
and second drive wheel assemblies, and said second fastening means
includes means individually releasably securing each of said first
and second drive wheel assemblies to said battery carrier assembly.
4. A collapsible portable electric wheel chair as set forth in
claim 3, wherein said second fastening means includes telescopic
connection means individually telescopically connecting each of
said first and second drive wheel assemblies to said battery carrier
assembly.
5. A collapsible portable electric wheel chair as set forth in
claim 1, wherein said frame includes two longitudinally rearwardly
extending substantially horizontal bar members, said longitudinal
bar members being laterally spaced apart, and a vertical bar member
extending vertically upwardly from each of said horizontal bar members;
and said first fastening means includes a tube on each of said first
and second drive wheel assemblies telescopically connected to one
of said longitudinal bar members, and a locking device on each of
said first and second drive wheel assemblies releasably secured
to one of said vertical bar members.
6. A collapsible portable electric wheel chair comprising a collapsible
frame, a seat on said frame, two ground engaging front wheels on
said frame, and a drive unit, said drive unit including a first
drive wheel assembly, a second drive wheel assembly, means supplying
electric power to each of said drive wheel assemblies for propelling
and steering said wheel chair, first fastening means manually releasably
securing said first and second drive wheel assemblies to said frame
whereby said first and second drive wheel assemblies are manually
removable from said frame when said frame is to be collapsed, each
of said drive wheel assemblies including an electric motor and a
ground engaging drive wheel and means drivingly connecting said
electric motor and said ground engaging drive wheel, second fastening
means manually releasably securing said first and second drive wheel
assemblies to one another whereby said first and second drive wheel
assemblies are manually separable from one another when removed
from said frame, said means supplying electric power to each of
said drive wheel assemblies including a joystick potentiometer and
an electrical components box, third fastening means rigidly securing
said electrical components box to said frame, and fourth fastening
means slidably securing said joystick potentiometer to said electrical
components box.
7. A collapsible portable electric wheel chair comprising a collapsible
frame, a collapsible seat on said frame, two rotatable front wheels
each pivotally mounted on said frame, and a drive unit, said drive
unit including a first drive wheel assembly, a second drive wheel
assembly, a battery carrier assembly disposed between said first
and second drive wheel assemblies, a battery on said battery carrier
assembly, and a control device supplying electric power from said
battery to each of said drive wheel assemblies for propelling and
steering said wheel chair, first fastening means manually releasably
securing said first and second drive wheel assemblies to said frame
whereby said first and second drive wheel assemblies are manually
removable from said frame when said frame is to be collapsed, each
of said drive wheel assemblies including an electric motor and a
ground engaging rear drive wheel and means drivingly connecting
said electric motor and said ground engaging rear drive wheel, and
second fastening means manually releasably securing each of said
first and second drive wheel assemblies to said battery carrier
assembly whereby said first and second drive wheel assemblies are
each manually separable from said battery carrier assembly when
removed from said frame.
8. A collapsible portable electric wheel chair as set forth in
claim 7 wherein said first and second drive wheel assemblies each
include adjustable means for moving said electric motor relative
to said ground engaging rear drive wheel.
9. A collapsible portable electric wheel chair as set forth in
claim 7, wherein said frame includes two longitudinally rearwardly
extending substantially horizontal bar members, said longitudinal
bar members being laterally spaced apart, and a vertical bar member
extending vertically upwardly from each of said horizontal bar members;
and said first fastening means includes on each of said first and
second drive wheel assemblies a tube telescopically connected to
one of said longitudinal bar members and a locking device releasably
secured to one of said vertical bar members and a gussett extending
between said last mentioned tube and locking device.
10. A collapsible portable electric wheel chair comprising a collapsible
frame, a collapsible seat on said frame, two rotatable front wheels
each pivotally mounted on said frame, and a drive unit, said drive
unit including a first drive wheel assembly, a second drive wheel
assembly, a battery carrier assembly disposed between said first
and second drive wheel assemblies, a battery on said battery carrier
assembly, and a control device supplying electric power from said
battery to each of said drive wheel assemblies for propelling ans
steering said wheel chair, first fastening means manually releasably
securing said first and second drive wheel assemblies to said frame
whereby said first and second drive wheel assemblies are manually
removable from said frame when said frame is to be collapsed, each
of said drive wheel assemblies including an electric motor and a
ground engaging rear drive wheel and means drivingly connecting
said electric motor and said ground engaging rear drive wheel, and
second fastening means manually releasably securing each of said
first and second drive wheel assemblies to said battery carrier
assembly whereby said first and second drive wheel assemblies are
each manually separable from said battery carrier assembly when
removed from said frame, said second fastening means includes two
laterally extending tubes on said battery carrier assembly and two
laterally extending tubes on said first drive wheel assembly and
two laterally extending tubes on said second drive wheel assembly,
said two tubes on said first drive wheel assembly being telescopically
connected to said two laterally extending tubes on said battery
carrier assembly, and said two tubes on said second drive wheel
assembly being telescopically connected to said two laterally extending
tubes on said battery carrier assembly.
11. A method of converting a collapsible portable manual wheel
chair to a collapsible portable electric wheel chair comprising
the steps of selecting a collapsible portable manual wheel chair
having a collapsible portable frame and two small front wheels pivotally
mounted on said frame and two large rear wheels mounted on said
frame, removing each of said large rear wheels from said frame,
and replacing each of said large rear wheels with an electro mechanical
drive wheel assembly having a drive wheel and an electric motor
and means drivingly connecting said electric motor and drive wheel.
12. A method as set forth in claim 11 wherein said replacing step
includes positioning said first and second drive wheel assemblies
in a first predetermined position, telescopically securing said
frame to said first and second drive wheel assemblies, and rotating
said assembled frame and first and second drive wheel assemblies
approximately 90 degrees about said drive wheels.
13. A method of converting a collapsible portable manual wheel
chair to a collapsible portable electric wheel chair and then collapsing
said electric wheel chair comprising the steps of selecting a collapsible
portable manual wheel chair having a collapsible portable frame
and two small front wheels pivotally mounted on said frame and two
large rear wheels mounted on said frame, removing each of said large
rear wheels from said frame, replacing each of said large rear wheels
with an electromechanical drive wheel assembly having a drive wheel
and an electric motor and means drivingly connecting said electric
motor and drive wheel, positioning said frame and drive wheel assemblies
in a driving position, rotating said frame and drive wheel assemblies
approximately 90 degrees about said drive wheels from said driving
position to a disassembly position, and removing said frame from
said drive wheel assemblies.
14. A method as set forth in claim 13 including the step of releasing
said drive wheel assemblies from one another after removing said
frame from said drive wheel assemblies.
15. A collapsible portable electric wheel chair comprising a collapsible
chair frame, a collapsible non-rigid chair back and a collapsible
non-rigid chair seat on said frame, two ground engaging front wheels
each pivotally mounted on said frame, and a drive unit, said drive
unit including a first drive wheel assembly, a second drive wheel
assembly, means supplying electric power to each of said drive wheel
assemblies for propelling and steering said wheel chair, fastening
means manually releasably securing said first and second drive wheel
assemblies to said frame whereby said first and second drive wheel
assemblies are manually removable from said frame when said frame
is to be collapsed, said fastening means including a tubular member
on each of said first and second drive wheel assemblies telescopically
connected to said collapsible chair frame, each of said drive wheel
assemblies including a support bracket and an electric motor mounted
on said support bracket and a ground engaging drive wheel mounted
on said support bracket and means drivingly connecting said electric
motor and said ground engaging drive wheel, and said tubular member
being an integral part of said support bracket.
16. A collapsible portable electric wheel chair as set forth in
claim 15, and second fastening means manually releasably securing
said first and second drive wheel assemblies to one another whereby
said first and second drive wheel assemblies are manually separable
from one another when removed from said frame.
17. A collapsible portable electric wheel chair as set forth in
claim 16, said second fastening means includes at least one laterally
extending tube on each of said support brackets and at least one
laterally extending tube on said battery carrier assembly, and at
least one of said tubes of said drive wheel assemblies being telescopically
connected to said laterally extending tube of said battery carrier
assembly.
18. A collapsible portable electric wheel chair as set forth in
claim 17, said electric motors each having a longitudinal axis disposed
in non-intersecting relation to a vertical plane extending longitudinally
through the center of said chair frame.
19. A collapsible portable electric wheel chair comprising a collapsible
chair frame, said collapsible chair frame including two rigid longitudinally
rearwardly extending substantially horizontal tubes and two rigid
substantially vertically extending legs, a collapsible non-rigid
chair back and a collapsible non-rigid chair seat on said frame,
two ground engaging front wheels each pivotally mounted on said
frame, and a drive unit, said drive unit including a battery carrier
and a first drive wheel assembly and a second drive wheel assembly,
said battery carrier including a laterally extending tube, at least
one of said drive wheel assemblies including mounting means and
an electric motor on said mounting means and a ground engaging drive
wheel on said mounting means and means drivingly connecting electric
motor and said ground engaging drive wheel, and said mounting means
including a longitudinally extending tube longitudinally telescopically
connected to one of said rearwardly extending frame tubes and a
laterally extending tube laterally telescopically connected to said
battery carrier tube.
20. A collapsible portable electric wheel chair comprising a collapsible
chair frame, said collapsible frame having two rigid seat support
bars and two rigid back support bars and two rigid leg bars and
two rigid longitudinally rearwardly extending subtantially horizontal
bars, a collapsible non-rigid chair back and a collapsible non-rigid
chair seat on said frame, two ground engaging front wheels each
pivotally mounted on said frame, and a drive unit, said drive unit
including a first drive wheel assembly, a second drive wheel assembly,
means supplying electric power to each of said drive wheel assemblies
for propelling and steering said wheel chair, fastening means manually
releasably securing said first and second drive wheel assemblies
to said frame whereby said first and second drive wheel assemblies
are manually removable from said frame when said frame is to be
collapsed, said fastening means including a tubular member on each
of said first and second drive wheel assemblies telescopically connected
to one of said rearwardly extending bars, and each of said drive
wheel assemblies including an electric motor and a ground engaging
drive wheel and means drivingly connecting said electric motor and
said ground engaging drive wheel.
Wheel chair description
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to electrically powered wheel chairs
and to a device and a method for converting a collapsible portable
manual wheel chair to a collapsible portable electrically powered
wheel chair.
Prior art devices and methods for converting portable manual wheel
chairs to electric wheel chairs are shown in U.S. Pat. Nos. 3,351,148,
3,893,529, and 3,896,891. These prior art devices and methods typically
include electric motor powered drive shafts which drive the conventional
large rear wheels of the wheel chair to propel and steer the wheel
chair.
The prior art has also provided a wide variety of power wheel chairs
such as shown in U.S. Pat. Nos. 3,376,944, 3,749,192 and 3,807,520.
These power wheel chairs are typically not usable as portable wheel
chairs, since they are not adapted to be readily taken apart and
collapsed manually in a short time period without the use of tools.
This disadvantage limits the use of such electric wheel chairs,
since they are not satisfactory for persons who want an electric
wheel chair which may be readily manually collapsed and transported
by automobile.
The present invention departs from these and other prior art devices
and methods by providing a device and a method for converting a
collapsible portable manual wheel chair to a collapsible portable
power wheel chair without relying upon use of the large rear wheels
of the manual wheel chair. According to the present invention, the
large rear wheels of the manual wheel chair are removed and replaced
with a collapsible portable electric drive unit which does not materially
detract from the portability of the wheel chair. This is accomplished
by providing a drive unit which includes a left drive wheel assembly,
a right drive wheel assembly, a center battery carrier assembly,
and a control device. The left and right drive wheel assemblies
each include a ground engaging drive wheel and an electric motor
drivingly connected to the wheel.
The left and right drive wheel assemblies are each removably connected
to the center battery carrier assembly. The left and right drive
wheel assemblies and the battery carrier assembly are then removably
connected to the wheel chair, and the control device is mounted
on the wheel chair and is electrically connected to the left and
right drive wheel assemblies.
When the converted electric wheel chair is to be collapsed such
as for transportation by an automobile, the left and right drive
wheel assemblies and the center battery carrier assembly are manually
disconnected from the wheel chair frame. The wheel chair frame is
then collapsed, and, since the large rear wheels of the wheel chair
are removed, the collapsed electric wheel chair frame is smaller
in size than the original manual collapsed wheel chair frame. The
left and right drive wheel assemblies are then each manually disconnected
from the battery carrier assembly and from one another. This results
in three portable light weight assemblies which can easily be placed
in the trunk of an automobile or in any other carrier for convenient
transportation.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the invention will be
more readily apparent upon an understanding of the preferred embodiment
of the invention shown in the accompanying drawings, wherein:
FIG. 1 is a perspective view of a collapsible portable electric
wheel chair illustrating the device and method of the present invention;
FIG. 2 is an enlarged perspective view of a battery carrier assembly
shown in FIG. 1;
FIG. 3 is an exploded perspective view of a right drive wheel assembly
weldment shown in FIG. 1;
FIG. 4 is a top plan view of a portion of the weldment shown in
FIG. 3;
FIG. 5 is a cross sectional side elevational view of a portion
of the weldment shown in FIG. 3;
FIG. 6 is a rear view of a portion of the weldment shown in FIG.
3; and
FIG. 7 is an enlarged exploded perspective view of a control unit
shown in FIG. 1.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to the drawings in greater detail, FIG. 1 shows a
collapsible portable manual wheel chair which has been converted
to a collapsible portable electric wheel chair. The electric wheel
chair shown in FIG. 1 includes a collapsible frame 11, two identical
front wheels 12, and an electromechanical drive unit 14.
The collapsible frame 11 is of tubular stainless steel and includes
a generally flat right side and a generally flat left side which
are mirror images of one another and which are interconnected by
two diagonal cross members 17 and 18. The diagonal cross members
17 and 18 are joined at their intersection by a pivot pin 19 and
are arranged so that they may be folded together about the pivot
pin 19 to reduce the size or bulk of the frame 11 in the manner
shown in U.S. Pat. No. 3,064,744, which is incorporated herein by
reference.
The collapsible frame 11 also includes a seat 22 and a back 23,
each of which is secured to the generally flat left side portion
and to the generally flat right side portion of the frame 11. The
seat 22 and back 23 are of a suitable foldable material such as
vinyl which is capable of supporting the weight of a person who
uses the chair and which is folded when the frame 11 is collapsed
about the pivot pin 19. The left and right side portions of the
frame 11 also include suitable foot rests, each of which is collapsible
by being folded about an axis so as to be movable from the position
shown in FIG. 1 to a position in which it is disposed in a vertical
plane substantially coplanar with the remaining portions of the
left and right side portions of the frame 11. A rear wheel axle
carrier 24 (only one of which may be seen in FIG. 1) is located
on each of the left and right side portions of the frame 11 for
rotatably supporting the two large rear wheels of the original manual
wheel chair (shown in phantom in FIG. 1) as explained more fully
below. Each of the front wheels 12 includes a yoke member (only
one of which may be seen in FIG. 1) which is pivotally mounted about
a vertical axis on the frame 11.
Referring now to FIGS. 1 and 2 together, the electromechanical
drive unit 14 includes a center battery carrier assembly 27. The
battery carrier assembly 27 includes a battery 28, a weldment 29,
and a vinyl battery cover 30. In the preferred embodiment, the battery
28 is a 24 volt lead acid storage battery and provides sufficient
capacity to drive the electric wheel chair for a full day between
charges. The vinyl cover 30 is placed over the battery 28 for appearance
purposes. The weldment 29 includes two axially extending square
steel tubes 31 and 32 and two laterally extending square steel tubes
33 and 34 which are welded together. The weldment 29 also includes
an L-shaped end tab welded on each end of the longitudinally extending
square tubes 31 and 32. The battery 28 rests on the laterally extending
square tubes 33 and 34 and is secured against lateral or longitudinal
movement by the L-shaped tabs and by the longitudinally extending
square tubes.
Referring now to FIGS. 1 and 3-6 together, the electromechanical
drive unit 14 also includes a left drive wheel assembly 39 and a
right drive wheel assembly 40. The drive wheel assemblies 39 and
40 are mirror images of one another and include an electric motor
and gear box 41, a ground engaging drive wheel 42, a weldment 43,
and a drive chain 44 which extends between a sprocket on the output
shaft of the electric motor and gear box 41 and a sprocket which
is secured to the drive wheel 42 for rotation therewith.
Each motor and gear box 41 in the preferred embodiment includes
a 24 volt D.C. permanent magnet electric motor which drives an output
shaft through a worm gear. Each motor and gear box 41 is connected
to its associated weldment 43 by four bolts.
Referring still to FIGS. 1 and 3-6, each weldment 43 includes a
single longitudinally extending square tube member 48 having its
forward end tapered outwardly. Two laterally extending square tube
members 49 and 50 are welded to the longitudinal member 48 and extend
laterally in a direction toward the center of the wheel chair. A
vertically upwardly extending stationary motor mounting post 51,
which may also be a square tube having its upwardly facing end closed
by a suitable square metal plate, is welded to the top surface of
the longitudinal member 48. A slidable motor mounting post 52, which
is also a square steel tube, is slidably mounted over the stationary
post 51. A motor mounting plate 53 is welded to the slidable post
52 and includes four holes which receive the four bolts described
above which secure the electric motor and gear box 41 to the weldment
43. A suitable hole is provided in the top of the motor mounting
plate 53 adjacent the post 52, and a suitable nut is welded in alignment
with the hole for receiving a bolt 54. The bottom end of the bolt
54 engages the top of the motor mounting post 51 as shown in FIG.
5 so that adjustment of the bolt 54 raises and lowers the slidable
motor mounting post 52 and plate 53. In this manner, the bolt 54
raises and lowers the motor and gear box 41 to permit adjusting
the tension on the chain 44.
A generally U-shaped reinforcing and connecting plate 58 is weldably
secured to the tube 48 by a gusset plate 59. A fastening plate 60
is operatively associated with the reinforcing and connecting plate
58 as best shown in FIGS. 1 and 4. A short length of cylindrical
steel tubing 61 is welded to the bottom of the tube 48 to provide
an axle carrier. An axle 62 is received in the axle carrier 61 and
is held in place by a suitable pin (not shown) which extends through
a hole 63 in the axle carrier 61 and through a suitable aligned
hole (FIG. 3) in the axle 62. The wheel 42 is rotatably journaled
on the axle 62 and is locked against lateral movement by the right
end face of the axle carrier 61 and by the enlarged head of the
axle 62.
Referring now to FIGS. 1 and 7, the electromechanical drive unit
14 also includes a control device 70 for supplying electric current
from the battery 28 to the drive motors 41 of the left and right
drive wheel assemblies 39 and 40. The control device 70 includes
a joy stick potentiometer 71 which is arranged to control the electrical
power provided to the electric motors to steer and propel the electric
wheel chair. The control device 70 also includes a components box
72 which houses the other electrical components of the control device
70 and which is constructed of two generally U-shaped flat sheet
metal members 73 and 74 which are secured together by suitable threaded
fasteners 75. The joy-stick potentiometer 71 is rigidly secured
to an elongated channel member 76, and the channel member 76 is
slidably secured to the components box 72 by a bracket 77 which
is secured to the components box 72 by suitable threaded fasteners.
The components box 72 is manually releasably rigidly secured to
the right side portion of the collapsible frame 11 by the removable
vertical tubular portions of the right arm rest (shown in phantom
in FIG. 7). A control cable 78 containing multiple wires insulated
from one another electrically connects the potentiometer 71 and
the components box 72 while permitting relative movement therebetween
when the operator slides the potentiometer 71 to a comfortable operating
position. A conduit 79 containing three multiple wire cables 80,
81 and 82 electrically connects the battery 28 to the electric motors
41. The cables 80, 81 and 82 each terminate at a suitable electrical
plug (FIG. 1) which is manually releasably connected to the lead
wires from the battery 28 and motors 41, respectively.
In order to convert the original collapsible manual wheel chair
to the collapsible portable electric wheel chair shown in FIG. 1,
the two original large rear wheels of the manual wheel chair (shown
in phantom in FIG. 1) are first removed from the rear wheel axle
carriers 24. The electromechanical drive unit 14 is then installed
in place of the original large rear wheels. This is accomplished
by attaching the components box 72 of the control device 70 to the
portion of the tubular frame 11 adjacent thereto. The left drive
wheel assembly 39 and battery carrier weldment 29 and right drive
wheel assembly 40 are then telescopically connected and placed on
the ground with the longitudinally extending square tubes 48 of
the drive wheel assemblies extending generally vertically upwardly.
The frame 11 is manually lifted over the generally vertically extending
square tubes 48, and the longitudinally rearwardly extending portions
of each side of the frame 11 are telescoped into the square tubes
48. The assembled unit is then rotated approximately 90.degree.
clockwise about the wheels 42 when viewed from the right as in FIG.
1 to rotate the longitudinally extending square tubes 48 to a generally
horizontal position and to lower the front wheels 12 to the ground.
The fastening plates 60 of the drive wheel assemblies are then pushed
vertically downwardly over the reinforcing and connecting plates
58 to lock the drive wheel assemblies and the battery carrier weldment
on the frame 11 and to reinforce the frame 11 by means of the gusset
59. The battery 28 and vinyl cover 30 are then placed on the battery
carrier weldment 29, and the three electrical plugs of the electrical
cables 80, 81 and 82 are connected to the lead wires from the battery
28 and the two electric motors 41.
When the converted portable electric wheel chair is to be collapsed,
the electrical plugs at the ends of the cables 80, 81 and 82 are
first disconnected. The battery 28 and vinyl cover 30 are then lifted
from the battery carrier weldment 29. The fastening plates 60 are
manually lifted vertically upwardly from the reinforcing and connecting
plates 58, and the wheel chair frame 11 is rotated approximately
90.degree. counter clockwise when viewed from the right as in FIG.
1 about the rear wheels 42 to a position in which the longitudinally
extending tubes 48 extend generally vertically upwardly. The frame
11 is then lifted vertically upwardly so that the frame 11 is pulled
from the tubes 48. The foot rests of the frame 11 are then folded,
and the frame 11 is collapsed by folding it about the pivot pin
19 to bring the left and right generally flat side portions of the
frame 11 together. Due to the narrow profile or lateral thickness
of the components box 72 and potentiometer 71, it is not necessary
to remove them from the frame 11. Additionally, because the original
large rear wheels of the frame 11 are removed, the size and weight
of such rear wheels is eliminated from the collapsed frame of the
electric wheel chair. The left and right drive wheel assemblies
39 and 40 are then manually disconnected from one another by manually
pulling the tubular members 49 and 50 of each of the drive wheel
assemblies laterally outwardly from the tubular members 33 and 34
of the battery carrier weldment 29. This collapsing of the converted
portable electric wheel chair is accomplished manually (that is,
without the use of tools) in a sufficiently short time (approximately
one minute) as to be satisfactory to approximately 100 percent of
the users of the converted chair, and the collapsed components of
the converted chair are each portable (that is, of a size and weight
which will fit in the storage area of an average or subcompact size
automobile and which are satisfactory to approximately 100 percent
of the users of the converted chair). |