Title: WHEEL CHAIR HAVING GEAR FOR RISING AND

FALLING

Technical Field

The present invention relates to a wheel chair having a lifting and

lowering gear, and in particular to a wheel chair in which a user can move along

an up step and a down step having a certain height by himself without any

assistance by an additional driving apparatus or other people.

Background Art

Generally, a wheel chair is provided for a disabled person or a patient.

The wheel chair is designed so that a user rotates a hand rim formed along a

wheel using hands and goes a desired way.

The conventional wheel chair will be described as follows with reference

to the accompanying drawings.

Figure 1 is a perspective view illustrating a conventional wheel chair.

As shown in Figure 1 , a conventional wheel chair comprises a seat 1

and back rest 2 which are fixed by frames, an arm rest 3 formed at both upper

ends of the seat 1 and the back rest 2, a handle 4 provided at a rear side, a foot

rest 5 provided at both lower sides of the seat 1 , small size steering wheels 6

which are rotatable at 360°, and driving wheels 8 having hand rims 7 provided

at rear sides for driving with hands.

The driving method of a manual type wheel chair will be described. In a

state that a user sits on the seat, the user rotates the hand rims 7 provided at

both sides. The driving wheels 8 run by the rotating force. The wheel chair

moves backward or forward based on the rotating direction. The direction is

changed by the steering wheels 6.

However, the above conventional wheel chair does not have any

problems when it moves on a flat ground or a road. However, when it meets a

protrusion or step while moving so as to cross a pedestrian way or a road, it is

impossible to go over the protrusion without any help from others.

In addition, when there is a protrusion higher than a building entrance or

a porch, other's helps are needed when crossing the protrusion using the wheel

chair. It is very inconvenient for a disabled person to ask help for an outdoor

activity. So, a disabled person is reluctant to go out, resulting in many

restrictions in life.

To overcome the above problems, a motored wheel chair is developed,

which is capable of moving over a protrusion without any helps from others.

However, the above conventional motored wheel chair has a complicated inner

construction. Since it needs a battery and motor, the price of the same is high.

When a battery is discharged or there is a problem in the driving operation, it is

impossible to move over the protrusion.

Disclosure of Invention

Accordingly, it is an object of the present invention to overcome the

above-described conventional problems.

It is another object of the present invention to provide a wheel chair

which is capable of moving over a protrusion without any helps from others or

an additional driving force.

To achieve the above objects, in a wheel chair which includes a steering

wheel, a driving wheel, and a main frame for fixing the steering wheel and the

driving wheel, there is provided a wheel chair comprising a gear rail guide which

is fixed at the main frame, with both ends of the same being bent in an arc

shape toward the ground; a gear rail which is engaged in a slidable structure

along the gear rail guide, with both ends of the same being engaged with a first

assistant wheel and a second assistant wheel; a driving unit which transfers the

gear rail along the gear rail guide so that the first or second assistant wheels

are positioned lower than the steering wheel and the driving wheel; and a

driving force transfer wheel for transferring a driving force between the steering

wheel and the driving wheel.

The gear rail guide is formed in a pipe shape and has a slit at a lower

surface in a longitudinal direction, and said gear rail is inserted into the interior

of the gear rail guide and has a plurality of teeth exposed to the outside through

the slit, and said driving unit comprises a driving gear which is engaged with the

teeth and the gear with a rotary shaft of the same being engaged with the main

frame, a gear lever which rotates the driving gear, and a stopper for selectively

controlling the rotation direction of the driving gear so that the driving gear is

rotated in one direction or the other direction.

The driving gear includes at least one mounting groove arranged at one

surface in a circular shape from the center of the rotary shaft, and said gear

lever has one end hinged at the center of the driving gear so that it rotates in

parallel with one surface of the driving gear and has an insertion protrusion for

the input or output from the mounting groove.

The gear rail guide has an elliptical cross section at an inner surface so

that only part of the inner surface contacts with an outer surface of the gear rail.

There are further provided a foot rest for resting user's feet thereon; and

a lifting lever for lifting up the foot rest, with the foot rest and the lifting lever

being integral, so that when the lifting lever is tilted backward, the foot rest is

tilted together.

There are further provided a joint link which is engaged with the lifting

lever and the driving force transfer wheel and inputs the driving force transfer

wheel into the portion between the steering wheel and the driving wheel when

the lifting lever is operated; and a transfer guide which is longitudinally formed

along a transfer path of the driving force transfer wheel and has a slot which is

slidably engaged at the driving force transfer wheel.

There are further provided an assistant frame of which one end is

hinged at the main frame, and the other end is positioned at a rear end of the

driving wheel; and a spring which applies an elastic force to the assistant frame

in the direction that the other end of the assistant frame gets closer to the

ground. The other end of the assistant frame is provided with a third assistant

wheel.

There is further provided a brake pad which is engaged at the main

frame in a rotatable structure and is designed to contact or not contact with the

gear rail based on the rotation angle for thereby fixing the position of the gear

rail.

Brief Description of the Drawings

The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein;

Figure 1 is a perspective view illustrating a conventional wheel chair;

Figure 2 is a lateral view illustrating a wheel chair according to the

present invention;

Figure 3 is a lateral view illustrating an engaged state of a gear rail and

a gear rail guide of a wheel chair according to the present invention;

Figure 4 is a horizontal cross sectional view illustrating an engaged

state of a gear rail and a gear rail guide of a wheel chair according to the

present invention;

Figure 5 is a lateral view illustrating an engaged state of a gear and a

gear lever of a wheel chair according to the present invention;

Figure 6 is a cross sectional view taken along line A-A of Figure 5;

Figures 7 through 12 are views illustrating an operation that a wheel

chair moves an up step according to the present invention; and

Figures 13 through 16 are views illustrating an operation that a wheel

chair moves a down step according to the present invention.

Best Mode for Carrying Out the Invention

The embodiments of the wheel chair according to the present invention

will be described with reference to the accompanying drawings.

Figure 2 is a lateral view illustrating a wheel chair according to the

present invention, Figure 3 is a lateral view illustrating an engaged state of a

gear rail and a gear rail guide of a wheel chair according to the present

invention, and Figure 4 is a horizontal cross sectional view illustrating an

engaged state of a gear rail and a gear rail guide of a wheel chair according to

the present invention.

As shown in Figures 2 through 4, the wheel chair according to the

present invention comprises a steering wheel 110 for adjusting an operation

direction, a driving wheel 120 for generating a driving force by a man's force, a

main frame 200 for fixing the engaged positioned of the steering wheel 110 and

the driving wheel 120, a gear rail guide 410 which is formed in a hollow pipe

shape in a longitudinal direction and includes a slip 412 formed at a lower

surface in a longitudinal direction, with both ends of the same being bent in a

direction of a ground surface and being fixed at the main frame 200, a gear rail

420 which is received in the interior of the gear rail guide 410 and slides along

the gear rail guide 410 and includes a plurality of teeth 422 exposed to the

outside through the slit 412, with both ends of the same being engaged with a

first assistant wheel 430 and a second assistant wheel 440, a driving unit which

transfers the gear rail 420 along the gear rail guide 410 so that the first or

second assistant wheels 420 or 430 is positioned lower than the steering wheel

110 and the driving wheel 120, and a driving force transfer wheel 320 for

transferring a driving force between the steering wheel 110 and the driving

wheel 120.

At this time, the driving unit comprises a driving gear which slides the

gear rail 420 along the gear rail guide 410 based on a rotation movement as it is

engaged with the teeth 422 and the gear 450, and its rotary shaft is engaged

with the main frame 200, a gear lever 460 of which one end is connected with

the driving gear 450 so that a user can easily rotate the driving gear 450, and a

stopper 470 which selectively controls the rotation direction of the driving gear

450 so that the driving gear 450 rotates in a certain direction or other direction.

When the entire outer surfaces of the gear rail 420 contacts with the inner

surface of the gear rail guide 410, since the gear rail 420 does not well slide due

to a friction force between the gear rail guide 410 and the gear rail 420, the

cross section of the inner surface is formed in an elliptical shape so that only

part of the inner surface of the same contacts with the outer surface of the gear

rail 420.

In a state of Figure 2, when the user rotates the gear lever 460 in the

counterclockwise direction, the gear rail 420 moves in the left direction along

the gear rail guide 410, and the first assistant wheel 430 moves downward. At

this time, in a state that the first assistant wheel 430 contacts with the ground,

when the gear lever 460 is further rotated in the counterclockwise direction, the

first assistant wheel 430 pushes the ground, and the steering wheel 110 is lifted

from the ground.

As shown in Figure 2, when the wheel chair is positioned at the end of

the down step so that the steering wheel 110 is positioned in the upper space of

the down step, and the gear lever 460 is rotated in the counterclockwise

direction, the gear rail 420 is moved in the left direction along the gear rail guide

410. The steering wheel 110 is moved in the downward direction and is placed

on the ground. When the steering wheel 110 is placed on the ground of the

down step, the user can move the wheel chair while maintaining the wheel chair

horizontal. The use of the wheel chair will be described in detail with reference

to Figures 7 through 16. Here, the gear rail can move along the groove formed

at the inner side of the gear rail guide. So, it can move in the inner direction of

the gear rail as long as the length of the outer side of the gear rail.

At this time, when the gear rail 420 is moved in the left direction, and

the force is not continuously applied to the gear lever 460 in a state that the

steering wheel 110 is lifted, the gear rail 420 is moved left by the weight of the

wheel chair, and the steering wheel 110 contacts again with the ground. So,

there is provided the stopper 470 at one side of the driving gear for controlling

the driving gear 450 so that the steering wheel 110 maintains a lifted-up state or

for controlling the rotation of the driving gear 450 so that the driving gear 450

rotates only in the counterclockwise direction even when the force is not

continuously applied to the gear lever 460.

Here, the stopper 470 is engaged with the main frame 200 with a hinge

structure so that the rotary shaft of the same is parallel with respect to the

driving gear 450. The stopper comprises a first fixture 472 slanted at a certain

angle in the counterclockwise direction rather than orienting to the direction of

the rotary shaft of the driving gear 450 with respect to the rotary shaft of the

stopper 470, and a second fixture 474 slanted at a certain angle in the

clockwise direction. As shown in Figure 2, the stopper 470 is positioned so that

the second fixture 474 is contacted with the teeth of the driving gear 450, the

driving gear 450 is rotatable in the counterclockwise direction, but is not

rotatable in the clockwise direction. So, the gear rail 420, which is once slid in

the left direction, does not slide in the right direction. Namely, even when the

force is not continuously applied to the gear lever 460, the steering wheel 110

maintains a lifted-up state.

The conventional wheel chair has a foot rest 300 for restring feet

thereon. In the present invention, the upper side of the foot rest 300 is hinged at

the main frame 200. There is further provided a lifting lever 310 for lifting the

foot rest 300 so that the foot rest 300 is not interfered with the up step. As

shown in Figure 2, when the wheel chair moves over the up step in a state of

Figure 2, the lifting lever 310 is rotated in the clockwise direction, so that the

foot rest 300 is lifted up.

According to the wheel chair of the present invention, the lifting lever

310 is engaged at the driving force transfer wheel 320. There are further

provided a joint link for inserting the driving transfer wheel 320 into the portion

between the steering wheel 110 and the driving wheel 120 when the lifting lever

310 is operated, and a transfer guide 330 which is formed along the transfer

path of the driving force transfer wheel 320 and has a slot 340 slidably engaged

with the driving force transfer wheel 320. So, when the lifting lever 310 is rotated

so that the foot rest 300 is lifted up, the joint link becomes a straight shape with

the lifting lever 310, and the driving force transfer wheel 320 is inputted between

the steering wheel 110 and the driving wheel 120, so that the driving force of the

driving wheel 120 is transferred to the steering wheel 110. The purpose of the

driving force transfer will be described with reference to Figures 7 through 16.

There are further provided an assistant frame 520 of which one end is

hinged at the main frame 200, and other end having a third assistant wheel 500

is positioned at a rear end of the driving wheel 120, and a spring 510 for

applying an elastic force to the assistant frame 520 in the direction that the

other end of the assistant frame 520 becomes near the ground. Here, the

assistant frame 520 and the spring 510 are provided for decreasing the impact

applied to the driving wheel 120 so that the first assistant wheel 500 is engaged

by the step when the wheel chair comes down from the step.

The wheel chair according to the present invention further comprises a

brake pad 610 which is designed to contact or not contact with the gear rail 420

based on the rotation angle for thereby stably fixing the position of the gear rail

420. At this time, the brake handle 600 is engaged at the brake pad 610 so that

the user can more easily rotate the brake pad 610.

Figure 5 is a lateral view illustrating an engaged state of a gear and a

gear lever of a wheel chair according to the present invention, and Figure 6 is a

cross sectional view taken along line A-A of Figure 5.

The user rotates the gear lever 460 in the clockwise direction or the

counterclockwise direction, so that the driving gear 450 rotates in the clockwise

direction or the counterclockwise direction. At this time, the gear lever 460 may

rotate integrally with the driving gear 450 based on the user's selection or may

rotate independently from the driving gear 450.

So as to implement the above operation, the driving gear 450 has at

least one mounting groove 454 arranged at one surface in a circular shape with

respect to the center of the rotary shaft. The gear lever 460 has one end hinged

(464) at the center shaft 452 of the driving gear 450 so that it rotates in parallel

with one surface of the driving gear 450 and has an insertion protrusion 462 for

being inputted or getting out of the mounting groove 454. Namely, the driving

lever 460 rotates with the driving gear 450 only when the insertion protrusion

462 is inserted into the mounting groove 454.

So, when the user operates the gear lever 460 for rotating the driving

gear 450, the user can repeatedly perform the engagement and disengagement

of the gear lever 460 and the driving gear 450 based on his convenience.

Figures 7 through 12 are views illustrating an operation that a wheel

chair moves an up step according to the present invention.

When the wheel chair according to the present invention moves the up

step, the lifting lever 310 is rotated as shown in Figure 7, and the foot rest 300

is lifted, so that the foot rest 300 and the first assistant wheel 430 do not

interfere with the up step. The gear lever 460 is rotated in the clockwise

direction, so that the first assistant wheel 430 is lifted up. As shown in Figure 8,

the wheel chair is needed to get close to the up step so that the first assistant

wheel 430 is positioned on the up step.

As shown in Figure 9, when the first assistant wheel 430 is positioned

on the up step, the gear lever 460 is rotated in the counterclockwise direction,

and the gear rail 420 is moved left, and the first assistant wheel 430 is

positioned on the up step, and the gear rail 420 is further moved left, and the

steering wheel 110 is lifter higher than the up step.

As shown in Figure 10, when the steering wheel 110 is lifted up, the

wheel chair is moved forward so that the steering wheel 110 is positioned on the

up step. As shown in Figure 11 , the gear lever 460 is rotated in the clockwise

direction, and the gear rail 420 is moved back. The second assistant wheel 440

is pushed against the ground, so that the driving wheel 120 is lifted up higher

than the up step. At this time, the driving wheel 120 and the steering wheel 110

are constructed to be drivingly connected with each other through the driving

force transfer wheel 320. When the user rotates the driving wheel 120, the

steering wheel 110 rotates in the reverse direction, so that as shown in Figure

12, the wheel chair moves forwards. When the driving wheel 120 is positioned

on the up step, the gear lever 460 is rotated in the counterclockwise direction,

and the gear rail 420 returns to its original position.

Figures 13 through 16 are views illustrating an operation that a wheel

chair moves a down step according to the present invention.

As shown therein, when the user wants to move the wheel chair to the

lower portion of the down step, as shown in Figure 13, the wheel chair is moved

forwards so that the first assistant wheel 430 is positioned at the upper portion

of the lower step, namely, the steering wheel 110 is positioned at the end of the

down step. As shown in Figure 14, the gear rail 420 is moved left by operating

the gear lever 460, and the first assistant wheel 430 is positioned at the lower

portion of the down step.

When the first assistant wheel 430 is positioned at the lower portion of

the down step, the wheel chair is slowly moved forwards by rotating the driving

wheel 120. At this time, the conventional wheel chair is slanted toward the

forward direction when the steering wheel 110 does not contact with the ground

as shown in Figure 15, so that the user may fall down resulting in damages.

However, in the present invention, even when the steering wheel 110 does not

contact with the ground, since it maintains a horizontal state by the first

assistant wheel 430 and the driving wheel 120, it is possible to prevent the user

sitting on the wheel chair from falling down.

When the driving wheel 120 is further rotated in the state of Figure 15,

as shown in Figure 16, the driving wheel 120 moves down from the down step,

so that the wheel chair is placed on the lower portion of the down step. When

the driving wheel 120 is moved to the lower portion of the down step, the

assistant frame 520 is hung over the upper portion of the down step and rotates

in the counterclockwise direction. At this time, the spring 510 is extended for

thereby generating an elastic force in the opposite direction of the rotation.

Since the moving down speed toward the down step is detected by the elastic

force of the spring 510, it is possible to release the impact force applied to the

driving wheel 120 when the wheel chair moves down.

A third assistant wheel 500 is provided at the end of the assistant frame

520 for decreasing the friction force with respect to the upper portion of the

down step. So, the user can more easily move the wheel chair in a state that

the assistant frame 520 contacts with the upper portion of the down step. At this

time, the stopper is designed to prevent the gear rail from being pushed

backward.

The user releases the stopper by pulling the brake and places down the

front wheels by releasing the brake. The front wheels are slowly placed down by

releasing the stopper and operating the brake after the gear rain is first fixed by

pulling the brake so as to prevent the first assistant wheel from being fast

touched with the ground as the gear rail 420 is pushed backward when

releasing the stopper.

Industrial Applicability

As described above, when the wheel chair according to the present

invention is used, it is possible to move up over the protrusion without other's

help or other driving forces. When moving down from the down step, it is

possible to move down from the protrusion without inclination of the wheel chair

or any impact.

As the present invention may be embodied in several forms without

departing from the spirit or essential characteristics thereof, it should also be

understood that the above-described examples are not limited by any of the

details of the foregoing description, unless otherwise specified, but rather

should be construed broadly within its spirit and scope as defined in the

appended claims, and therefore all changes and modifications that fall within

the meets and bounds of the claims, or equivalences of such meets and bounds

are therefore intended to be embraced by the appended claims.