Note: Descriptions are shown in the official language in which they were submitted.
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2~
D~SCRIPT:I ON
TITI,E: ~E{E:EI,C~I~IR ANr) ~TTACII~ENT THEREFO~<
~5) TECHNICAL FIELD
This invention concerns improvements in wheelchairs,
and more particularly relates to an improved wheelch~ir
wherein the wheelchair-reliant person can without
assistance modify the dimensional and mobility charac-
510) texistics of said wheelchair.BA~KGROUND ART
Wheelchairs are generally constructed having a pair
of small forward wheelsl each supported by an overhead
pivoted yoke which permits the wheel to turn 360~ about
(15) a vertical axis, and a pair of opposed lar~e rear wheels
positioned at each side of the chair on horizontally
disposed axles which permit xotation of said rear wheels
in fixed vertical planes. The rear wheels, when sim~l-
taneously pushed or pulled by the disabled occupant
(20) propel the wheelchair in foxward or reanYard directions.
~ hen one rear wheel is pushed more than thP other,
or when one rear wheel is pushed while the other is
maintained motionless or pulled in the reverse direction,
the wheelchair can be made to perform turning motions.
(25) One motion however, that the conventional wheelchair is
incapable of is a lateral or sideways translational
motion in the direction of the hoxizontal axles of the
rear wheels. Such sideways motion is particularly
valuable in confined quarters which cannot accommodate
(30~ the size or turning radius of the large rear wheels, and
~.~
-. (2) ~92~
--~ where omniclirectional movement is necessa~.
Wheelchairs haviny remo~able rear wheels have bee
disclosed in U.S. Patent 4,098,521 and elsewhere. ..
~$~ Although removal o the rear ~h~els substantially conver-ts
the ~rheelchair fro~ a self-propelled to an attendant-
propelled state, the feature of optional removability of
the rear wheels affords the following advantages:
a) easier storage of the wheelchair, particularly in
~10) an automobile,
b) el ;m; n~tes the need of the user to lift or be
lifted above the top of the rear wheels for side-
ways transfer from or to the seat which is gener-
ally below the top of the rear wheels, and
(15) c) narrowing of the lateral size of the wheelchair,
thereby facilitating passage through narrow aisles~
Although U.S. Patent 4~0g~,~21 discloses that the
large wheels may be removed while the occupant is in ~he
wheelchair, it is unlikely that this can be accomplishea
~20) by the occupant without assistance because to do so
requires the rearward tilting of the wheelchair to a very
precarious position while simultaneously disengaging the
large wheels.
It is accoxdingly an object of the present invention
('5) to provide a wheelchair having opposed large rear wheels
mounted on horizontal axles, said wheels being removable
by the seated occupant of saia wheelchair~
It is a fuxther object to provide a wheelchair of
the aforesaid nature wherein said wheels may be safely
removed by said occupant unaidedly by the performance oE
. ~,~p,
(3~ g ~
two separate and sequential manipula-tions.
It is another object of this invention to prov;de a
wheelchair cap~ble of motion in the direction oE said
tS) hori~ontal axles.
It is a ~urthex object to provide a wheelchair of
the aforesaid nature ~hich, by a sing~e manipulation
rapidly achievable by the seated occupant, can be modified
so as to have rolling mo~ility in the direction of said
(10) hori~ontal axles~
It is a still further object of this invention ~o
provide apparatus which can be attached to a conventional
wheelchair to achieve the fore~oing objects.
These objects and other objects and advantages of the
(15) invention will be apparent from the following description.
- DISCLOSURE O~ INVENTION
The above and other beneficial objects and advantages
are accomplished in accordance with the present invention
~y an -~provement in an other~ise cQnv~nt~n~l wheelchair
(20) comprised of a frame having paired rear vertical posts,
front caster wheels mounted on said frame, seating means
associated with said frame generally behind and above
said front caster wheels, and a pair of rear drive wheels
rotatably supported by said rear vertical posts on oppo-
(25) site sides of said seating means and adapted to rotate in
vertical planes about horizontally disposed axles, said
drive wheels preferably being equipped with quick discon-
nect means to facilitate their removal from and return
to said wheelchair.
; t30) The improvement of the present invention comprises
32
jac~ing apparatus capa~le of li-fting at least the re~r
por-~ion of the wheelchair to an eleva-ted heigh t where
said drive wheels are no longer res~ing upon the support
t5~ surfàce for said wheelchair, and a pair of xear caster
wh~els~ journalled to said frc~me in association with said
jacking apparatus in a manner to engage said support
surface when the rear portion of the wheelchair is lifted.
The jacking apparatus is preferably associated with the
~lO) axles of said drive wheels. ~ever components of said
- jacking apparatus axe situated within reach of the occu-
pant seated in the wheelchair, and are adapted for
movement in a substantially vertical plane to cause the
jacking apparatus to raise or lower the rear-caster
~15) wheels, whereby the rear portion o the wheelchair is
- respectively lowered or raised.
In a preferred embodiment, the rear caster wheels
are telescopically engaged with the frame in a downwardly
~irected ~a~ner sllch that, when not in operative position
(20) ~he distance between ~he center of the driue wheel axle
and the lowermost portion of an associated rear caster
wheel is less than the radius of the drive wheel. In such
non-operative or standby position, the rear caster wheels
do not contact the support surface. When placed in
(25) operational position by means of said levers, the distance
between the center of the drive wheel axle and lowermos-t
portion of the associated rear caster wheels becomes
greater than the radius of the drive wheels, thereby
causing the lowermost portions of the drive wheels to
(30) rise from contact with the support surface.
- (5)
The wheelchair may be oE a conventional foldable
construction, ancl said seat:ing means ma~ h~ve ~lexi~le
seatrest ana backrest portions. Removable foot and leg
~5) supports may be associated wi-th the for~ard end of the
wheelchair. Armrest members may be associated with said
seating means, and clothing protectors mav be vertically
disposed between said armrest members and the lowermost
extremity of said seating means. A circular handrail
~10) may be coaxially disposed about each of said drivP wheels
to facilitate their manipulation.
The term caster wheel, as employed herein, is
intended to denote a wheel pivotably mounted ~rom above
in a m~nner permitting rotation in a vertical plane and
~15) 360Q of turning about a vertical axis The manner of
mounting generally involves a yoke which spans said
wheel in engagement with opposite extremities of the
wheel's hori20ntally disposed axle, and pivotably engagPs
~n overhead ~upport. In the preferred emhodiment of the
(20) improved wheelchair of the present invention, when the
rear castex wheels are activated ~o support the ~Jheel-
chair, ~aid wheelchair is capable of movement in any
direction whether or not the drive wheels are removed
because it is supported by four caster wheels. In such
(25) state, movement of the wheelchair is accomplished by the
occupant by applying pulling or pushing ~orce to nearby
objects such as walls in a con~ined area.
The lever-operated jacking apparatus may be installed
onto newly manufactuxed wheelchairs designed to accommo-
(30) date said jacking apparatus, or said jacking apparatus,
. ~6~ 2~2
with sli~ht structural modification, ma~ be adapted forinstallation onto existin~ conven-tional wheelchairs~
BRIEF DESCRIPTION OF DR~T,~INGS
(5) For a fuller understanding o the nature and objects
o the invention, reference should be had to the Eo].lowing
detailea descrip~ion taken in connection wlth the
accompanying drawing forming a part of this specification
and in which similar numerals or reference indicate
(10) corresponding parts in all the figures of the drawing:
~ igure 1 is a rear perspective view o-f a wheelchair
equipped with an embodiment of 3acking apparatus of the
present invention, showing said wheelchair in its
upwardly jacked position.
~153 Figure 2 is ar. enlarged fxagmentary sectional view
taken along the line 2-2 of Figure 1, showing the wheel-
chair in its upwardly jacked position.
Figure 3 is an enlarged fragmentary side view ~aken
ng ~he l.:e 3-~. of Figure . with '~e d.~ive whe~l
(20) removed and showing the wheelchair in its lower, unjacked
position. `
Figure 4 is a side view taken along the line ~-4 of
Figure 2.
Figl~re 5 is an enlarged sectional view taken along
(25) the line 5-5 of Figure 1.
BEST MODE OF CARR~ING OUT THE INVENTION
Referring to Figure 1, a wheelchair is shown
comprised of a metal tu~ular frame 10 having paired front
vertical posts 11 and paired rear vertical posts 12
(30) Diagonal support members 13 extending between lower
(7) ~ %
- horizont~l connecting members 15 and upper horizont~l
connectin~ member~. 16 of frame 10 are înterenga~ed by
pivot pin 1~ which ellables the wheelc}lair to undergo a
(5) foldin~-type motion causing lateral compaction thereof.
Front caster wheels 17 enga~e the lowexmost extremities
o~ front vertical posts 11~ Si-tuated rearward and above
front caster wheels 17 is seatin~ means 20 comprised of
back sling 18 and seat sling 19 fabricated of compliant
~10) web-like ~a~exials and supported by por~ions of said
frame. A pair of spo~ed rear drive wheels 21 having
horizontally disposed hubs 22 and associated axles 30 are
adapted for rotation in vertlcal planes about said axlPs.
A le~er-opexated jacking device 23 is associated
~15) with each rear vertical post 12 on the innermost or
facing sides of said posts. The exemplified embodiment
of jacking device shown in detail in Figures 2-4 is
designed to be applied as an accessory feature ~o conven-
tional wheelchairs~ Said jacking device is comprised of
~20~ a suppoxt bracket 31 adapted to be fastened to post 12
by bolt 32 which penetrates channel 33 in said post and
is secured by thread in bracket 31. ~ bu~tressing protru-
sion 43 affixed to bracket 31 engages post 12 to prevent
rotation o said bracket about bolt 32. An axle housing
(25) 35 in said bracket disposed within protrusion 43 and
parallel to channel 33 is adapted to provide journalled
support for axle 30 of drive wheel 21~ A lever 24 is
attached to bracket 31 by first pivot means 25 J thereby
permitting pivotal movement of said lever in a vertical
~30) plane. The forwardmost portion of said lever is
designatecl action portion 4~, ana the rearwarclmost
portion of said lever is c~esignated handle 39. A
vertical connecting rod 26 is pendantly attached by ~
(5) second pivot means comprisecl of bushing ~7 and pin 40
attached to said lever in action portion 44. The lower-
most extremity of said vertical connecting rod engages
a third pivot means comprised of bus`ning 46 and hori~on-
tally disposed pin 27 attached to colu~n 28 which
(10) suppor~s`rear caster wheel 29. Col~n 28 is adapted to
t~lescopically engage tubular housing 30 pendantly
supported by sleeve 37 fitted on~o horizontal connecting
member 15 and joined thereto by bolts 38~
In the illustrated embodiment, connecting rod 26 is
(15) shown to be of a~justable length by virtue of upper and
lower threaded engagement ~eans 41 and 42 respectively
associated with bushings 47 and 46, and which possess
opposite threading and thereby enable connecting.rod 26
~o unc~tion in a ~urnbuckle manner ~nen rotated ~G lt its
(20) long ax-.s. To facilitate such rotation, said connecting
rod may be provided with a knurled surface.
When the jacking device is activated to cause li~t~
ing, lever 24 will he in a su~stantially hori~ontal
position, as shown in Figure 2. In said position, it is
(25) .important to note that first pivot means 25 is above
second pivot means 40, and the lever is in abutment with
the innenmost extremit~ of axle housing 35 ~7hich emerges
fxom the inside face 45 of buttressing protrusion 43.
Such manner of abutment prevents further downward movement
(30) of handle portion 39. The position of the second pivot
(9) ~ 32
mean~ h resp~c-t t~ the first pivo-t me~ns, and the
ang~ oE CC)ntl~C tinc~ rod 26 bett~een said second and third
pivot means ~re such th~t Eorces directed upw~rdly ~rorn
~5) r~ar cas-ter wheel 29 urge lever 24 in the direction of
abutment with axle housing 35. Such factors of desig~
and construc~ion thereby constitute lGcking means which
concertively act to maintain lever 24 in a ~ixed hori-
20ntal position. The elements of said locking means
(10) comprise an abutmen~ means such as axle housing 35, and
a -force emanating rom rear caster wheel 29 and trans-
mitted to said second pivot means in a mannex sexving to
pivot said lever abou~ said first pivot means in the
direction of said abutment means~ Properly directed force
(15) transmission to the second pivot means may be secured by
either proper placement o~ the second pivo~ means with
. .
respect -to the first pivot means, or proper angle of the
connecting rod.
The distance of separation between the centers of
(20~ said fitst and second pivot means i5 essentially the
distance between the uppermost and lowermost positions
~f the rear caster wheel. It is to be noted that, when
lever 24 is in its upright position as shown in Figure 3,
first and second pivot means are centered on a substan-
(25) tially horizontal line.
Although the invention has been exempli~fied primarilyin terms o~ an embodiment wherein the jacking apparatus
may be`added -to an existing conventional wheelchair, it
is to be understood that the same inventive principles
(30) may be applied to a wheelchair speci~ically manufactured
(10) ~ ~ 92~82
~o incc~rpora~e -the feat-lres oE the jac};ing appara-tus
herein described. ~n sclicl lcltter instance, th~ rea~~
caster wheel, instead of bein~ mounted on a sleeve~like
(5) fitting adapted to it onto the lower horizont~l -
- connecting member, may be telescopically fitted to an
extension of rear vertical post 12 below said lower
horizontal connectin~ member. Furthermore, certain
features of the bxac~et member may be incorporated into
(103 vertical post 1~. In any embodiment of the jacking
apparatus of this invention, it is prefexable to locate
the rear caster wheel no closer to the front o~ the wheel-
chair than the axles of sai~ drive wheels, the reason
being to prevent the wheelchair from toppling over
(15) rea~ardly.
Braking means, operable by the seated occupant of
the wheelchair may be provided to afford greater control
over the motion of the wheelchair when it is in its
jacked-up mode and capable of omnidirectional movement.
(2~) ~uch braki1l~ slea~s may be lever-act~vated devices wnich
cause frictional restraint between the fxame and the
ground or rear caster wheels.
The quic~ly detachable drive wheels utili2ed in the
pre~erred embodimen~ of wheelchair of the present inven-
(25) tiGn are of standard manufacture. In Figure 5, whichschematically illustrates the general features of a
detachable drive wheel, a sliding rod 50 position~d
within channel 51 in axle 30 rests in abutment with
untensioned spring 52 confined in the closed end 53 of
~30) axle 30. A detent 54 which extends outwardly from axle 30
~`- and com~lurlicates with channel 51 is associated with a
tensioned sprin~ 55 which maintains a force on detent 5~
tending to draw it inwarclly toward channel 51. The innex
(5~ end of said detent is normally in abutment with the
cylindrical surface o~ rod 50, said abutment causing the
outer end o said detent to protrude ~rom axle 30.
However, when rod 50 is pressed toward the closed end of
axle 30, a depressed portion 56 is brought beneath
(10) detent 54. Such action causes detent 54 to temporarily
enter axle 30, thereby releasing axle 30 and its asso-
ciated drive wheel from fixed engagement with axle
housing 35.
While particular examples of the present invention
(15) have been shown and describea, it is apparent that
~hanyes and modifications may be made therein without
departing from the invention in its broadest aspects~
The aim of the appended claims, therefore, is to cover all
such changes and modifications as fall within the true
(20) spirit and scop~ of the in~ention.
I
t25)
(30)
