Note: Descriptions are shown in the official language in which they were submitted.
~3~4~C~3
The present invention relates to a wheelchair in which
the wheels are arranged to be driven by circular hand rails
fixedly attached to, concentric with and laterally spaced outside
the wheels of the wheelchair. In particular the present
invention relates to a manually operable propulsion unit for the
detachable attachment to such a wheelchair which allows the
occupant of the wheelchair to propel the wheelchair by means of
the backwards and forward motion of a hand lever in addition to
the direct drive by means of the hand rails. The present
invention also provid~s a converslon kit which on erection
provides said unit as well as a wheelchair equipped with said
unit.
The normal propulsion of a wheelchair is accomplished
by pushing a hand rail attached to the main wheels, or using a
hand lever device, or using an electric motor. The steering of
the wheelchair is accomplished either by a steering mechanism, or
by individually braking the motion of the two main wheels by hand
and in such sequence as to change the direction of the
wheelchair. Such wheelchairs are disclosed, for example ln V.S.
Patent No. 4,354 to Queen's University, issued 91 October 1982,
U.S. Patent No., 4,560,181, issued December 24, 1985 to Design
Loft Inc., U.S. Patent No. 3,189,368 to James F. Peterson, issued
15 June 1965, U.S. Patent No. 3,994,509, lssued 28 January 1986
to Jerome E. Schaeffer, U.S. Patent No. ~,453,729, issued 12 June
1984 to Wesley o. Lacken, Canadian Patent No. 1,202,554, issued 1
Apri]. 1986 to Akira Korosue and Canadlan Patent No. 1,026,662
issued 21 February 1978 to Permobilstiftelsen.
All previously known devices used to propel a
wheelchair with handle bars are very cumbersome, complicated,
very heavy and require that the wheelchair has to undergo
extenslve and expensive alterations and changes to accommodate
such devices or a completely new and special wheelchair has to be
designed and manufactured at exorbitant cost in order to utilize
the use of a hand lever propulsion system. The use of a hand
-- 1 --
., ~
4~03
lever propulsion system is very desirable as it provides a
substantial power to propel the wheelchair, eliminates the
tremendous stress and jolting of the arms and especially the
shoulders and shoulder joints of the wheelchair user. This is a
very severe problem, as documented by the discomfort and
inflammation of the shoulder ~oints experienced by Rick ~Ianson on
his world tour. Many patients confined to a wheelchair do not
have the physical strenyth to propel the wheelchair by pushing
the hand rail ring by hand and must rely on the assistance of a
person pushing their wheelchair. Electrically propelled
wheelchairs which could solve some of the problems, are
exorbitantly expensive, heavy, require constant service and are
difficult to transpor-t.
The invention of applicant's copending application No.
583l5~ filed ~ugust 22, 1988 and entitled Detachable Manual
Propulsion System provides a manually operable propulsion unit
which is a self-contained unlt and can be detachably attached to
any type of hand rail pushed chair without alterations of the
chair very quickly requiring a minimum of tools. Thus the uni-t
can be transported to any desired place and quickly mounted on
the wheelchair so as to convert the ~hselchair so that it is
propellable by the backwards and forwards motion of the hand
levers of the propulsion unit in addition to being propellabl~
directly by the hand rails.
In applicant's copending application No.5~3~56 flled
August 22, 1988 and entitled Detachable Manual Propulsion Unit
the invention provides a linkage means detachably attached to
each said hand rail on the wheelchair and connecting said hand
rail with a hand lever pivotably mounted on base member means
adapted to be detachably attached transversely of the frame of
the wheelchair such tha-t back and forwards motion of the hand
lever in a vertical plane drives its associated wheel of the
wheelchair via the attached hand rail.
130~ 3
According to a particular embodiment of the invention
of the copending applicatlon there is provided a manually
operable propulsion unit for de-tachable attachment to a
wheelchair in which the wheels are arranged to be driven by
circular hand rails fixedly attached to, concentric with and
laterally spaced outwardly from the wheels of the chair
comprising a pair of rigid support members each adapted to be
detachably attached to one said hand rail within the periphery
thereof, a rigid elongated base member means adapted to be
detachably attached transversely of the frame of said wheelchair,
a pair of hand levers pivotally mounted about the horizontal axis
of said base member at either side of the wheelchair, a pair of
mounting means each on one said rigid support member and a pair
of rigid linkages each pivotally mounted at one end to one said
mounting means at a point off-center from the center of the hand
rail and to an intermediate point on said hand lever whereby the
back and forwards motion in a vertical plane of each said hand
lever drives its associated wheel of the wheelchair via its
attached hand rail. Suitably the rigid support members are
straight bars or other shaped cross-bars, such as Y-shaped and X-
shaped depending on the type of the wheelchair and the location
of the connections between the handrail and the wheel of the
wheelchair.
In a particularly desirabl~ embodiment of the invention
of the copending application there is provided a manually
operable propulsion unit for detachable attachment to a
wheelchair in which the wh els are arranged -to be driven by
circular hand rails fixedly attached to, concentric with and
laterally spaced outside the wheel of the wheelchair comprising a
pair of crossbars each adapted to he detachably attached
diametrically across one said hand rail, a basebar adapted to be
detachably attached across the frame of said wheelchair, a palr
of mounting means on each one of said crossbars extending across
said hand rail and a pair of connectlng bars each pivotably
mounted at either end to said mounting means at a point off-
,
-- 3 --
~3~ )3
centre from the centre of the hand rail and to an intermediatepoint on said hand lever bar whereby back and forwards motion in
a vertical plane of each of said hand lever bars drives its
associated whPel of the wheelchair via its attached hand rail.
Suitably the mounting means is a plate fixedly attached to the
crossbar extending across the hand rail. The crossbars adapted
to be detachably attached diametrically across the hand rail
include adjustment means therein so as to be able to force fitted
across internal faces of the hand rail by the adjustment means,
which adjustment means preferably comprises a thread and nut
means, which adjustment means preferably comprlses a thread and
nut means in the crossbar for varying its length. In particular
the adjustment means desirably comprises a threaded ad~ustment
bolt which slides into a hole drilled lengthwise into the center
of the crossbar and an adjustment in length is made by turning
the nut on the bolt. Alternatively a right and left turn thread
is afixed to the adjustment nut to lengthen or shorten the
crossbar to fit securely into a position across the inside of the
hand rail. The crossbar suitably has a length of 1 1/2 to 2 feet
and is a 1 1/2 to 2 inches square bar of aluminum or steel and
has a thread and nut for adjustment to the diameter of the hand
rail of the chair. Suitably the ends of the bar are semi-
circularly recessed to accommodate the hand rail and more
desirably one side of each end of the bar has a round dovetail so
as to slide onto the bolts which attach the hand rail to the
wheel of the wheelchair which prohibits the tendency of the bar
to slide around the hand rail.
The mounting means is suitably a plate located at the
centre of the crossbar having a mounting hole *or the end of the
connecting bar at a distance from the centerpoint of the wheel
and thus the hand rail which is concentric therewith. It is
desirable that the plate has several holes at different distances
from the centerpoint of the wheel, this gives stroke and leverage
adjustment as desired by the occupant of the wheelchair. The
lower end of the connecting bar is suitably attached to the plant
~.3~41~3
by a bol-t and bushing.
In a further embodiment of the invention of the
copending application the hand lever bar has means for attaching
the connection at differe~t points intermediate the end of the
bar to provide for stroke lenyth adjustment. Thus the hand lever
bar which is suitably about 3 feet in length and 1 1/2 inch
square made o aluminum or steel bar is connected to the basebar
by a plastic bushing or roller bearing for easy manoeuvreability.
The len~th of the ~oint is usually 2 to ~ inches. The hand lever
bars desirabl~ include handles which are adjustable to extend
vertically or horizontally from said lever bar. The handles on
top of the hand lever bars are suitably plastic with a metal
screw and each can be changed to vertical to horizontal operating
positio~ by either screwing it on vertically or sideways as
desired. The hand lever bars are attached to a basebar suitably
at the base at the front wheelchair frame in front of the big
wheels and behind the small wheels. The basebar acts as a
stabilizer to ensure stability of a folding wheelchair and acts
on both sides as a base connection o~ the lever bar. The basebar
is detachably clamped to the wheelchair frame, which clamps
suitably have wing nuts for easy removal and mounting.
In a particularly desirable embodimen-t of the invention
of the copending application in the lower rear frame of the
wheelchair another basebar is clamped to provide cross stability,
this having particularly good results with collapsible
wheelchairs. The front and rear stabilizer basebar may have a
centre joint and two side ~oints and appropriate stabilizer
clamps and thus will be foldable with the chair without the
necessity of detaching the propulsion unit of the present
invention. Alternatively the rear stabilizer basebar is suitably
a longitudinally adjustable bar suitably by means of screw means
therein which is located between the hubs of the large rear
wheels of the chair. Alternatively the front basebar may have
its central portion between the frame bars of the wheelchair
130A103
similarly longitudinally extendable by screw means, the ends of
the central portion between the frame bars of the wheelchair
being removably located in socket end portions of the outer
por-tions of the front basebar. Thus, the centre portion can be
removed for collapse of the wheelchair. The folding joints
suitably have wing nuts for easy removal and moun-ting.
The upper end of the connecting bar suitably extends
into an in~slot in the middle of the hand lever bar and desirably
a number of holes, suitably three or four holes, are located
approximately 1 1/2 to 2 inches apart to allow for stroke length
adjustment. The connec-ting bar, is suitably a flat crossbar, and
is inserted and secured by a bolt into the selected hole ln the
slot in the lever bar for the desired stroke length. The
crossbar is suitably of solid aluminum or steel of a 1/4 inch
thickness and 1 1/2 inches width and approximately 1 3/4 to 2
feet in length.
Thus, the invention of the copending application
provides a manually operatable propulsion unit for detachable
attachment to any type of hand rail pushed wheelchair without
alterations to the wheelchair in a very few minutes, usually less
than 5 minutes, no tools are required, unless for convenience a
simple wrench may be used. The unit is light weight weighing
approximately about 4 lbs. and adds only a small amount, such as
an inch, to the width of the chair and therefore poses no
problems in getting!through normal door openings or operating in
confined spaces. The propulsion unit is of utmost simplic~ty and
reliability and virtually maintenance free. The unit in kit form
can easily be taken on journeys, by plane or bus, etcO, by
carrying it in a light plastic ~arrying bag approximately one
tenth the size of a golf bag. The wheelchair can be left at the
beginning of the journey and any other similar wheelchair can
take its place at the end of the trip. Upon arrival at the
travel destination the unit can be easily attached to any rented
or otherwise provided hand rail driven wheelchair by simply
-- 6 --
~04~3
changing the length o~ the basebars and the adjustable length of
the crossbar. The steering works on the same princlple as
manoeuvring a conventional wheelchair pushing the hand rail.
Especially elderly and weaker patients can use the unit easily
and without assistance. secause of the very easy and continuous
forward and backward rnovement of the lever bars this provldes
constant gentle exercise to -the arm and shoulder muscles. This
is of great therapeutic value. The marked improvement in the
independence and mobility of the patient through use of this unit
will have a very positive effect on the psycological welfare of
the patient. The handles can be positioned straight upward or
level to the left or right to supply a grip position for th0
hands and, at the same time, can provide a resting support for
the hands. The device propels the wheelchair forward and
backward and steering the wheelchair by holding back or
accelerating the movement of the lever bars, or halting the
movement of the hand lever bars completely to stop the
wheelchair. The unit is very simple and does not require any
service or maintenance.
It has now further been found according to the present
invention that the basebar which extends across the frame of the
wheelchair and upon the ends of which hand levers are pivotally
mounted in the propulsion unit of the copending application may
be replaced with advantage by a pair of base clamps adapted to be
clamped on the frame of the wheelchair at transversely opposite
sides thereof, each of the base clamps having a horizontally
extending portion for pivotably mountlng on the hand lever.
These base clamps eliminate the necessity for having the basebar
and also the stabilizer bar and thus significantly simplify the
structure of the unit and with the absence of the basebar and the
stabilizer bars the wheelchair folds wihtout the necessity for
removal and reattachment of such bars. Furtherr the unit may be
attached to and removed *rom the wheelchair much more easily and
quickiy with the presence of these base clamps instead of the
basebar.
~3~ 1D3
According to the invention therefore there ls provided
a manually operable propulsion unit for detachable attachment to
a wheelchair in which the wheels are arranged to be driven by
circular hand rails fixedly attached to, concentric with and
laterally spaced outside the wheels of the wheelchair comprising
base member means adapted to be detachably attached transversely
of the frame o~ said wheelchair, a pair of hand levers pivotably
mounted about a horizontal axis of said base member means at
either side of the wheelchair, a pair of linkage means each
detachably connected between one said hand rail and said hand
lever such that back and forward motion in a vertical plane of
each of said hand levers drives its associated wheel of the
wheelchair via its attached hand rall, said base member means
comprising a pair of base clamps adapted to be clamped on the
frame of the wheelchair at transversely opposite sides thereof,
each said base clamps having a horizontally extending portion for
pivotally mounted said hand lever.
The present invention also provides a conversion kit
for erection of a manually operable propulsion unit for
detachable attachment to a wheelchair in which the wheels are
arranged to be driven by circular hand rails fixedly attached to,
concentric with and laterally spaced outside the wheels of the
wheelchair, said kit comprising base member means adapted to be
detachably attached transversely of the frame of said wheelchair,
a pair of hand levers adapted to be pivotally mounted about a
horizontal axis on said base member each adapted to be detachably
connected between one said hand rail and said hand lever such
that back and forwards motion in a vertical plane of each of said
hand levers in the unit drives its associated wheel of the
wheelchair via its attached hand rail, said base member means
comprising a pair of base clamps adapted to be clamped on the
frame of the wheelchair at transversely opposite sides thereof,
each said base clamps having a horizontally extending portlon for
pivotally mounting said hand lever.
'13~ 3
In a preferred embodimen-t oE the presenk invention each
of the base clamps is adapted to be clamped between a pair o
tubes on the frame of the wheelchair. Desirably each of the base
clamps is adapted t~ be clamped between a pair of vertlcally
spaced adjacent tubes on the frame of the wheelchair.
In a particular embodiment of the present invention
each of the base clamps is L-shaped with an obtuse angle between
the leg and foot portions with the leg and foot portions each
being adapted to be clamped to one of the tubes of the frame of
the wheelchair, the foot portion having a bearing for pivotably
mounting the hand lever extending outwardly transversely
therefrom. Suitably each of the base clamps is longitudinally
split into a pair of symmetrical parts, each of the parts having
on its inner surface recesses for accommodating the tube of the
frame of the wheelchair and screw means for clamping the parts
together around the tubes of the frame of the wheelchair.
Preferably -the screw means are wing bolts. However, it will be
realized that the shape of the base clamp will depend on the
particular structure of the frame of the wheelchair and the clamp
may be of other shapes such as straight or L-shape.
The present invention will be further illustrated by
way of the accompanying drawings, in which:-
Figure 1 is a perspective view of a wheelchairincluding the manually operable propulsion unit including a base
clamp according to a preferred embodiment of the present
invention; and
Figure 2 is an exploded side elevation of the bas~
clamp as shown in Figure 1.
Referring to the Figures, the manually operable
propulsion unit comprises a pair of vertically extending hand
lever bars 1, each lever bar 1 pivotably mounted at its bottom
~.3(~4~1)3
end to the end of a base clamp 40 mounted in the frame 3 of the
wheelchair 4 such that the occupant of the wheelchalr 4 can
provide back and forwards mo-tion in a vertical plane of the hand
lever bars 1. As seen particularly from ~'igure 2 each the ba~e
clamp 2 has at its end a spigot 5 on which a sleeve 6 on the end
of each lever bar 1 rota-tes. Sleeve 6 is held by spring cotter
pin (not shown), its rotation facilitated by a plastic bushing
extending the full length of the sleeve 6. A washer is located
on each side oE the sleeve 6. The upper end of each lever bar 1
has a rubber grip handle 20.
As shown in Fig. 2 the base clamp 40 is of L-shaped
configuration and is longitudinally split to a pair of
symmetrical members 41 having recesses 42 on the Eacing surfaces
ad~acent the ends thereof to accommodate the tubes of the frame 3
of the wheelchair 4. The symmetrical members 41 are clamped
together over vertically ad~acent tubes of the frame 3 of the
wheelchair 4 by means of wing bolts 43 such that the spigots 5
extend outwardly transversely of the frame 3 of the wheelchair 4
and are suitably in alignment. While the base clamp 40 is shown
as L-shaped with an obtuse angle between the leg and foot por-
tions depending on the structure of the frame 3 of the wheelchair
4, the base clamp may be of o-ther shapes so as to be clamped
between adjacent tubes of -the frame 3 of the wheelchair 4 and
may, for example, be straight or of T-shaped configuration and
may, of course, be clamped between more than two tubes of the
frame 3 of the wheelchair 4.
Each base clamp ~0 is clamped to the wheelchalr frame 3
in front of the big wheels and behind the small wheels. There
are approximately 5 inches of frame 3 on which the base clamp 40
can be moved forwardly and backwardly thereby adjusting the
handle position and the stroke length of the lever bar 1.
Extending across the circular handrail 11 of the
wheelchair 4 by which the wheels 12 of the wheelchair 4 are
-- 10 --
~3~4~
normally drlven is a Y-shaped bar 13. The Y-shaped bar 13 is
securely fastened by turning a nut of an extension bolt 14 in the
bar 13. The bar 13 has a mounting plate 15 fixedly attached
thereto having a moun-ting hole therein which is off-center from
the hub of the wheel 12 of the wheelchair 4 and also from the
handrail.
Extending between the lever bar 1 and the mounting
plate 15 is a connecting bar 16. A sliding connecting clamp 17
is attached to the lever har 1 and the connecting bar 16 is
attached into a receiving slot of the connecting clamp 17 and is
held in place by a bolt. The connecting clamp 17 can be moved up
and down the lever bar 1 thereby adjusting the stroke length and
leverage to any desired position re~uired by the occupant of the
wheelchair 4. The connecting bar 16 can move freely as required
by the circumference of the circle described by the mounting
plate 15 of the Y-shaped bar 13. The distance of the point of
attachment of the connecting bar 16 to the mounting plate 15 on
th~ U-shaped bar 13 from the center of the wheel 12 and the off-
center distance of the point of attachment in relation to the
imaginary center crosslines are of vital importance as the
particular position produces the zero leverage distance which the
propulsion unit has to overcome to approximat.ely 1 inch instead
of approximately 6 inches necessary if the connecting bar 16 were
attached directly to ths Y-shaped bar 13 and not off-center. It
will be recognized that the propulsion unit has a mirror image
structure on each side of the wheelchair 4 and that each of the
hand lever bars 1 can be operated lndependently of the other and
thus the wheelchair 4 can be guided by the mode of the operation
of the hand lever bars 1. It will be further recognized that the
propulsion of the present invention can be attached to any
standard handrail driven wheelchair 4 and thus the structure of
the wheelchair does not form a critical part of the present
invention can be used with both foldlng and permanently expanded
wheelchairs. However, for use with folding wheelchairs it is not
necessary to remove the propulsion unit of the present invention
~3 [)~ 3
in order to fold the wheelchair. It is only desirable to remove
the propulsion unit of the pr0sent lnvention when it is desired
to transport it to another location to a-ttach it to another
wheelchair.
For wheelchairs with air tires there are usually more
than four bolts holding the handrail 11 to the main wheel 12.
For such wheelchairs, as shown in Figure 1, the bar 13 may be Y-
shaped and this generally covers any and all known handrail
lo designs. Alternatively it can be X-shaped.
To remove the whole unit from the wheelchair 4, only
two wing bolts 42 on each side have to be taken off to remove the
base clamps 40. Then the extension bolts 14 on the two Y-Cross
bars 13 have to be loosened to remove the whole propulsion unit
from the wheelchair 4. No tools are required, because everything
is adequately secured by hand tightening. This has also reduced
the weight of the unit. The removal and reattachment time has
been reduced to a maximum of 3 minutes.
- 12
