Wheel chair abstract
A stair-climbing apparatus for a wheel chair or the like mobile
transport means, which apparatus is provided with an undercarriage,
a plurality of pulleys mounted in the undercarriage, at least one
endless track extending along a way defined by at least two pulleys,
a drive mechanism adapted for engagement of at least one of the
pulleys and a frame for supporting the wheel chair or a similar
mobile transport means, whereby the frame comprises a platform which
relatively to the undercarriage is adapted for swiveling movement
about a shaft extending at the climbing side of the undercarriage
parallel to the pulley axes through drive means adapted for coaction
with a steering mechanism which is adapted for keeping the platform
horizontal independently of the position of the undercarriage. The
drive mechanism is retarded when the platform deviates a set angle
from the horizontal.
Wheel chair claims
I claim:
1. A stair-climbing apparatus for a wheel chair or the like mobile
transport means, which apparatus is provided with an undercarriage,
a plurality of pulleys mounted on the undercarriage, at least one
endless track extending along a way defined by at least two of the
pulleys, a drive mechanism for driving at least one of the pulleys
and a frame for supporting the wheel chair or other mobile transport
means, characterized in that the frame comprises a platform, means
for adjusting the position of the platform relative to the undercarriage
for maintaining the platform in a substantially horizontal position,
the adjusting means comprising an elongated element including a
counter-element member and a screwed spindle member receivable in
the counter-element member and rotatable relative to the counter-element
member to adjust the length of said elongated element, one of the
members being pivotably connected to the undercarriage and the other
of the members being pivotably connected to the platform, a motor
for driving the screwed spindle member for varying the length of
the elongated element, and means for controlling the drive mechanism
to retard the drive mechanism in response to deviation of the platform
from the horizontal.
2. A stair-climbing apparatus according to claim 1, characterized
in that the platform is provided with at least one hinged section
for facilitating moving the wheel chair on or off the platform.
3. A stair-climbing apparatus according to claim 1, characterized
in that the controlling means disconnects the drive mechanism when
the deviation of the platform from the horizontal exceeds a first
given angle and does not influence the drive mechanism when the
deviation is below a second given angle.
4. A stair-climbing apparatus according to claim 3, characterized
in that the value of said first given angle is 6.degree.-8.degree.,
and the value of said second given angle is 2.degree.-3.degree..
Wheel chair description
The invention relates to a stair-climbing apparatus for a wheel
chair or the like mobile transport means, which apparatus is provided
with an undercarriage, a plurality of pulleys mounted in the undercarriage,
at least one endless caterpillar track extending along a path defined
by at least two pulleys, a driving device which is adapted to drive
at least one of the pulleys and a frame for supporting the wheel
chair or a similar mobile transport means.
In such a prior apparatus a frame is disposed on the tracked undercarriage
which comprises a frame portion connectible to the back and the
wheels of a wheel chair and a sliding portion connected at an angle
rigidly to the frame portion, which sliding portion is adapted for
coaction with guiding and stopping ways.
By sliding the frame in its one outer position, the sliding portion
is brought in a position allowing tilting of the frame, so that
the frame portion can be connected to the back of the wheel chair,
whereby the wheels of the wheel chair should find support against
a pair of laterally extending tube portions of the frame portion.
This attachment method entails a number of drawbacks. In view of
the great variety existing in the field of wheel chairs, a number
of wheel chairs will not be suitable for thus being reliably coupled
to the frame. For instance, a wheel chair to be coupled should be
provided with sufficiently stable and accessible supporting points
in its back. In practice this implies that wheel chairs whose grips
are removable at the top side of the back cannot be coupled to the
frame in the desired manner. Furthermore the necessity of abutment
of the wheels of the wheel chair against the protruding tube portions
means that the stair-climbing apparatus is only usable for wheel
chairs whose wheel diameters lie in a restricted range.
After the coupling of a suitable wheel chair to the frame, this
should be tilted backwards together with the wheel chair until the
sliding direction of the sliding portion runs parallel to the sliding
direction of the guiding ways. The frame with coupled backwardly
tilted wheel chair should then be pushed to the other outer position
and be stopped in this position. By switching on the driving device,
the stair-climbing apparatus can be driven towards the stair after
which through coaction between steps and tracks the stair-climbing
apparatus is moved upwards or downwards along the stair, whereby
the portion of the guiding ways to which the frame is coupled should
always be present adjacent the undercarriage portion then having
the highest position on the stair. Through the then inclined position
of the undercarriage, the wheel chair will come in a more or less
horizontal position depending on the angle of inclination of the
stair. This now means that the passenger transported in the wheel
chair, from the tilting of the frame to minimally the time when
the stair-climbing apparatus is entirely present on the stair, is
positioned in an extremely inconvenient and submissive condition,
which position in case of relatively flat stairs continues to be
maintained partly. After leaving the stair the undercarriage again
returns in its horizontal position, which again brings the transported
passenger in the hardly enviable backwardly inclined position, until
the drive is disconnected, the frame is pushed to its other outer
position and is tilted forwardly. It is the object of the invention
to render the stair-climbing apparatus substantially independent
of the type of wheel chair to be transported or the like mobile
transport means, consequently to render same suitable for all possible
vehicles provided with wheels, and thereby to also keep this transported
conveying means along the entire transport path as much as possible
in horizontal position.
This is achieved according to the invention with a stair-climbing
apparatus of the above described type when the frame comprises a
platform which relatively to the undercarriage is pivotal about
a shaft extending at the climbing side of the undercarriage parallel
to the pulley axes by means of driving means which coact with a
steering mechanism which is adapted to keep the platform horizontal
independently of the position of the undercarriage. Through these
features it becomes possible to position any wheel vehicle on the
platform in order to bring same up and/or down a stair, whereby
during the transport movement the control mechanism subjects the
platform to such a pivoting movement that this, and hence the vehicle
placed thereon, will always be in an at least substantially horizontal
position. A further advantage of the platform is that this allows
in principle movement up and down on two sides. This is especially
advantageous when a stair terminates in a relatively narrow passage
where the prior art apparatus provides additional difficulties,
since this has to be turned in order to deposit the wheel chair,
seen in the driving direction, behind the stair-climbing apparatus.
Although different methods are possible for depositing or removing
a wheeled vehicle from the platform, it is preferable according
to one embodiment of the invention that the platform is provided
with at least one folding drive-up and drive-off platform. This
enables the stair-climbing apparatus to be stopped adjacent the
top end of the stair and after the folding down of a platform mounted
in the climbing direction to the front of the platform, to drive
off the wheel chair at floor level from the stair-climbing apparatus.
In such an embodiment it is likewise possible advantageously to
avoid by means of switching contacts that the driving device is
activated as long as a platform is not yet in a folded-back, locked
position, which offers an additional protection.
The pivoting of the platform can be realized with many means, such
as with hydraulic or pneumatic cylinders, chains, ropes, racks and
pinions etc. However it is preferred that the driving means consist
of a motor and a drivable screwed spindle, the one end of which
is pivotally connected to the platform and which is adapted for
coaction with a counter element which is connected to the undercarriage,
since such a drive in case of failure of the power source, has a
self-braking effect.
If in accordance with a further embodiment of the invention the
steering mechanism is adapted for transmitting a signal which is
adapted for influencing besides the driving means likewise the driving
device, in such a way that the drive of the stair-climbing apparatus
is delayed according as the angle enclosed by the platform with
the horizontal becomes larger, the comfort of the stair-climbing
apparatus is still increased in that inter alia the transition from
a flat floor to a stair inclination is traversed in an impact-free
and flexible manner. It is preferred thereby that the steering mechanism
disconnects the drive when a given value of said angle is exceeded
and the drive is not influenced underneath a given value of said
angle, whereby in practice an optimum is attained when the values
of said angle are respectively 6.degree.-8.degree. and 2.degree.-3.degree..
One embodiment of the stair-climbing apparatus according to the
invention will now be described, by way of example, with reference
to the accompanying diagrammatic drawing, wherein:
FIG. 1 is a side view of the stair-climbing apparatus according
to the invention; and
FIG. 2 is a rear view of the stair-climbing apparatus according
to FIG. 1.
The stair-climbing apparatus shown on the drawing is provided with
an undercarriage 1 fitted with two slide-shaped girders 2 and 3
which are connected by a plurality of transverse girders 4. In the
slide-shaped girders 2 and 3 respectively, there is mounted a drive
pulley 5 and a bend pulley 6. The drive pulleys 5 are drivable through
a reduction gearbox 7 by a motor 8 which is mounted on one or both
slide-shaped girders. Around a drive pulley 5 and a bend pulley
6 mounted on the same slide-shaped girder there runs a track 9,
while the bottom side of a slide-shaped girder constitutes a guide
and support way for the track 9 passing therealong. At the outer
side the track 9 is provided with transversely extending ribs adapted
for engagement on the treads of a stair to be ascended or descended.
At the inner side the track 9 is provided with tooth-shaped projections
adapted for engagement with corresponding projections on the outer
circumferential face of the drive pulley 5.
On the undercarriage 1 there is positioned a frame 10 consisting
of a platform 11 and platforms 12 and 13 hinged thereto. Furthermore,
a rail 14 is secured on the platform via two standards 15, while
two standards are extended to handles 18 extending underneath the
platform, by means of which the stair-climbing apparatus can be
steered when this is present on a long and/or steep stair. The steering
person will then be present behind the stair-climbing apparatus,
seen in the climbing direction.
At the bottom side of the platform 11 there is secured a support
16 which is connected through a pivot 17 to a transverse girder
4 which forms a connection between the overhead ends of the two
slide-shaped girders. A second support 19 secured to the bottom
side of the platform 11 is coupled via a pivot 20 to a screwed spindle
21 which is partly received in a counter-element 22. The screwed
spindle 21 and the counter-element 22 are mutually rotatable by
means of a motor 23 which, together with the counter-element, is
hingedly connected about a shaft 24 to the undercarriage 1.
To the platform there is secured furthermore a steering mechanism
25 which, depending on the inclination made by the platform 11 relatively
to the horizontal, is adapted for transmitting a control signal
which causes the motor 23 to rotate clockwise or counter-clockwise
in order to bring and/or maintain the platform 11 in a substantially
horizontal position.
Besides, the control signal also influences the drive motor 8 progressively,
i.e. the larger the angle between the horizontal and the platform
11, the lower becomes the advancing speed of the stair-climbing
apparatus, on the understanding that when a given angle is exceeded,
e.g., 6.degree.-8.degree., the drive motor is stopped. On the other
hand, a relatively small deviation from the horizontal, e.g. less
than 2.degree.-3.degree., will have no influence on the drive motor
8. Through this arrangement the comfort of the transported passenger
is optimally enhanced, inter alia in that the transition from a
flat floor to a stair gradient takes place shock-free and smoothly.
The operation of the above described stair-climbing apparatus is
as follows:
For moving a wheel chair or similar wheel vehicle on the platform,
one of the platforms, e.g. 12, is to be swung down so that this
constitutes an ascent for the wheel chair. To facilitate in this
case the ascending movement, the platform 11 may be brought in a
position parallel to the upper part of a track. The wheel chair
on the platform 11 is moved as much as possible towards the platform
13 and secured in situ with appropriate means. After raising and
locking the platform 12 the drive may be engaged, while the steering
mechanism 25 transmits a signal which activates the motor 23 until
the platform 11 is in a horizontal position. During or after this
horizontal positioning of the platform 11, the drive motor 8 may
be activated, and the stair-climbing apparatus can be moved in the
direction of a stair. In case the respective stair has to be ascended,
the bend pulley 6 should be oriented towards the stair. In case
of descent, the drive pulley 5 should face the stair. By coaction
of the ribs on the tracks with the treads, the stair-climbing apparatus
can be moved in the desired direction over and along the stair.
In case a stair is ascended, the stair-climbing apparatus can be
stopped before attaining the top of the stair, viz. when the pivot
between the platform 11 and the platform 13 is at the level of the
upper tread. After the lowering of the platform 13, the wheel chair
can be driven away from the platform 11 at floor level via the platform
13.
Naturally, many alterations and variants are possible within the
scope of the invention. For instance, the lockings, not shown, of
the platforms 12 and 13 may be provided with contacts which prevent
the engagement of the drive when the platforms are not in the raised
and locked position. Likewise, it is possible to replace the slide-shaped
girders with bend pulleys 6 by straight girders with bend pulleys
having a diameter that is twice or thrice as large as that of the
drive pulley 5. The platform may furthermore be provided with grooves
or guideways for the wheels of a wheel chair or the like transport
means, as diagrammatically shown on the drawing. Such grooves or
guideways may then be simply provided with locking means easily
adaptable to the wheels. These locking means may naturally also
be connected to the platform 13 and again be fitted with switching
elements preventing the activation of the drive as long as the wheel
chair has not been properly locked. |