Wheel chair abstract
A foldable wheel chair wherein diagonal braces which are transversely
foldable are coupled by universal joints to front and rear portions
between two longitudinally foldable opposite side frames to prevent
slidable motion. Caster wheels and drive wheels are mounted on the
side frames thereby folding the wheel chair in longitudinal and
transversal directions to render it compact.
Wheel chair claims
What is claimed is:
1. A foldable wheel chair comprising a three-dimensional link mechanism
with two opposite side frames including horizontal upper frames
with central portions base posts, said central portions being fixed
to upper ends of said base posts, front and rear lower frames pivotally
mounted on said base posts to swing from the vertical to the horizontal
position universal joints, and a pair of diagonal braces pivotally
mounted by said universal joints on said upper frames, the front
lower frame at their forward ends, and on the upper and rear lower
frames, said diagonal braces being folded simultaneously by folding
the front and rear lower frames to reduce the distance between said
two opposite side frames and simultaneously bring a caster wheel
and a drive wheel mounted on the front and rear lower frames closer
together.
2. A foldable wheel chair as defined in claim 1 wherein said base
posts have at their lower ends downwardly directed channel members
with central portions fixed to said base posts, said channel member
receiving therein the front and rear lower frames, said front and
rear lower frames being pivotally journaled to said channel members,
said front and rear lower frames abutting against said channel members
when they are in horizontal position.
3. A foldable wheel chair as defined in claim 1 including a vertically
slidable back post in each of the upper frames rearwardly thereof.
4. A foldable wheel chair as defined in claim 1 including a channel
member mounted pivotally said front and rear lower frames, said
base posts having a wall with a vertical slot wherein said channel
member is slidable along said base posts.
Wheel chair description
BACKGROUND OF THE INVENTION
This invention relates to a foldable or collapsible wheel chair
and more particularly to a readily portable wheel chair which is
three-dimensionally foldable to render it compact.
A conventional wheel chair of these species has been heretofore
proposed so that diagonal braces have central portions journaled
between two opposite side frames have upper pivot portions longitudinally
slidable, thereby folding and reducing the size of the chair inwardly
thereof. This does not, however, enable physically handicapped persons
to transport or carry the chair. In other words such a wheel chair
is only arranged in order for economizing space out of use.
According to the present invention a foldable wheel chair is adapted
so that a pair of foldable diagonal braces are connected to two
foldable opposite side frames to form a two-dimensional link mechanism
and thus fold the chair in a three-dimensional manner thereby rendering
it compact. As a result physically handicapped persons may carry
the chair indoor or in an automobile or the like and readily assemble
it therein without aid of the others, and have easy riding to reach
a desired destination thus increasing their sphere of action.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to
provide a wheel chair which includes a horizontal lower frame. Two
opposite side frames are downwardly folded to longitudinally and
transversely reduce the wheel chair in dimensions. A pair of diagonal
braces are connected to the lower frame and are telescoped along
a plane perpendicular to the side frame to prevent slidable motion.
Another object of the present invention is to provide a wheel chair
which employs a three-dimensional link mechanism such as frame components
each fabricated from square tube or pipe to ensure mutual mechanical
operation thereof.
A further object of the present invention is to provide a wheel
chair which has minimum components and is of simple design, and
which affords the use of light metal material to reduce the chair
wheel in weight to approximately 12kg, so that physically handicapped
persons can transport and carry the wheel chair without aid of the
others.
Still another object of the present invention is to provide a wheel
chair which is provided with an armrest supporting back post telescopically
and vertically mounted to an upper frame over which a sheet for
the chair seat is spread to thus prevent the wheel chair from increasing
its height due to longitudinal and transverse reduction of the chair
in dimensions.
Yet another object of the present invention is to provide a wheel
chair which is adapted so that front and rear lower frames of each
of side frames is longitudinally folded and slidable laid on a base
post to further reduce the wheel chair in height when folded.
Further objects and additional features of the invention will become
apparent from the following detailed description and annexed drawings,
wherein:
FIG. 1 is a front view of a wheel chair according to an embodiment
of the present invention;
FIG. 2 is a view similar to FIG. 1 but showing the wheel chair
folded in a longitudinal direction;
FIG. 3 is a section of the wheel chair shown in FIG. 1, as viewed
from the side elevation when part are partially broken away;
FIG. 4 is a section of the wheel chair of FIG. 3, folded in a transverse
direction, as viewed from the side elevation;
FIG. 5 is a perspective view, enlarged of front and rear lower
frames in a pivotal movement;
FIG. 6 is a perspective view, enlarged of an upper frame to which
a diagonal brace is journaled by an universal joint.
FIG. 7 is a section of a wheel chair according to another embodiment
of the present invention, as viewed from the side elevation; and
FIG. 8 is a perspective view, with enlarged back post in which
the front and rear lower frame is mounted.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the accompanying drawings wherein similar characters
designated similar parts, two opposite side frames are generally
indicated at 10.
A foldable wheel chair structure comprises a pair of the side frames
which include upper frames 11, base posts 12 downwardly extending
from the upper frames at the intermediate sections thereof, and
downwardly directed channel members 13. All the components for the
wheel chair structure are fabricated from light metal rectangular
pipes. Front and rear lower frames 14, 15 are received in each of
the channel members 13 and pivotally mounted therein by pivot bolts
16, 17. The lower frames 14, 15 are held vertical side by side,
as shown in FIG. 4 when the wheel chair is folded, but they are
adapted to align with each other in a horizontal relation when the
wheel chair is unfolded, as the lower frames are engaged with the
channel member 13. The upper frames 11 are in cooperation with the
each other to define a chair element. One pair of universal joints
20 are disposed inwardly of the upper frame at the opposite ends
thereof, and the other pair of universal joints 20 are arranged
inwardly of the lower frames at first ends thereof, respectively
to pivotally support front and rear diagonal braces 18 along a plane
perpendicular to the side frames 10. A support shaft 21 passes through
the side frame 10 and extends inwardly thereof. A mount member 22
having a U-shaped section is rotatably journaled to one end of the
shaft 12 by its base 23. The mount member 22 includes side walls
24 between which a pin 25 is fixed. The diagonal brace 18 is pivotally
journaled to the pin 25. The diagonal brace 18 comprises one brace
18' and another brace 18" passing through the slit of the former.
They are pivoted by a pivot bolt 19 at the center thereof to pivotally
cross each other.
A sheet or web 30 for a chair seat is spread over the two upper
frames 11. The lower frames 14, 15 are folded as shown in FIG. 4
if the seat 30 is raised by hand from below, to thus fold the braces
18' and 18" downwardly as shown in FIG. 2. At that time the
braces are pivoted along the lower braces 14, 15 and inwardly of
the wheel chair.
A pair of housings 34 are mounted by brackets 33 on the respective
lower frames 14 at the inner sides thereof and are provided with
spindles for forks 35 on caster wheels 36.
The front lower frame 14 is bifurcated at the other end thereof
to pivotally mount thereon a bracket 38 having a square sleeve 37,
at one end thereof, by means of a pivot bolt 39. A footrest support
41 carries a foldable footrest and is telescopically received in
the sleeve 37. The footrest 40 when folded is upwardly pivoted to
allow the footrest support 41 to enter into the sleeve 37. The footrest
support is then swung to minimize space.
The rear frame 15 is provided at its center with a shaft support
43 on which a shaft 45 for a drive wheel 44 is mounted. The drive
wheel 44 carries a hand rim 47 over a bracket 46 secured to the
wheel.
The upper frame 11 includes an opening 50 through which a back
post 51 passes vertically and slidably. A plurality of apertures
52 are formed in the back post 51 to receive a pin 53 passing through
the upper frame 11 at the rear end thereof. With this arrangement,
the apertures 52 may be indexed by the pin 53 to thus adjust the
height of the back post. The back post 51 is provided at its upper
end with a horizontally extending armrest 54 and a push handle 55
for the wheel chair, which extends in the direction opposite to
the armrest. A back sheet 56 is spread between the two back posts
51 to be removably mounted thereon by means of hooks 57. In folding
the wheel chair, the back sheet 56 is removed from the back posts,
and the pin 51 is also removed to then lower the back post and in
alignment with one of the apertures to maintain the back post in
position as shown in FIG. 4.
On the other hand, if the front and rear lower frames 14, 15 are
folded, the caster wheel 36 and the drive wheel 44 are moved toward
the center of the wheel chair to reduce the latter in width by about
1/2.
In FIGS. 7 and 8, there is shown a second embodiment of the invention
wherein a vertical and hollow base post 112 has a slit 16 along
its one wall and has a C-shape. The downwardly directed channel
member 13 has at its outer wall a bracket 161 and a slider 162 fixed
thereto to slidably engage in the base posts 112. The channel member
13 receives therein the front and rear lower frames 14, 15 which
are pivoted by the pivot bolts 16, 17 to swing the frames from the
horizontal position to the vertical position for joining the frames.
Thus, the frames 14, 15 are opened horizontally to abut against
the under surface of the channel member 13 and is held in position.
A stopper 163 is mounted forwardly of the base post 112 to partially
cover the slit 16 to prevent the slider 162 from being removed from
the base posts 112.
With this arrangement, the base posts 112 are slidably engaged
by the frames 14, 15 to thus further reduce the wheel chair in height
by sliding thereinto.
Although the invention has been described with reference to specific
means for practicing the invention, it is apparent that many modifications
may be made by one skilled in the art, and accordingly, it is intended
that the scope of the invention be limited only as defined in the
following claims. |