Note: Descriptions are shown in the official language in which they were submitted.
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Convertible Lift Asseinbly
Field of the Invention
The present invention relates generally to the field of vertical lifts, and in
particular, to lift mechanisms that convert to stairs.
Back~Tround of the Invention
Stairways employed in buildings and other structures present difficulties to
non-ainbulatory individuals. For example, a non-ambulatory individual confined
to a
personal vehicle such as a wheelchair cannot easily negotiate common
stairwells. To
accommodate such individuals, separate elevator lifts, moving chair
arrangements, or
ramps are often provided. In stair structures extending a vertical distance
that is less than
a building story, such as those typically used near the entrance to a
building, a separate
elevator lift is not always practical, particularly in outdoor environments.
In such cases,
separate i-amps or moving chair arrangements may be provided which facilitate
vertical
travel by a personal vehicle.
One drawback to the use of a separate ramp to provide personal vehicle access
to
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elevated surfaces is that suitable ramps consume relatively large amounts of
space. As a
result, existing buildings must often be substantially altered to accommodate
the
installation of a ramp. In many circumstances, space constraints within or
surrounding
the building make installation of a ramp impossible.
Moving chair arrangements offer a solution in such low rise environments.
Moving chair arrangements comprise a chair that slides diagonally up and down
the
stairway. Such arrangements require that the personal vehicle be separately
transported
up or down the stairway. Because personal vehicles can be quite heavy, sepai-
ate
transport of the personal vehicle can be difficult. Moreover, the movable
chair itself,
when not in use, still occupies stairway space and thus dictates the
appearance of the
staircase.
Separate vertical wheelchair lifts have also been employed for such low rise
environments for use in situations in which there is inadequate room for an
access ramp.
Sueh devices, however, while consuming less space than a ramp, nevertheless
consume
valuable access space and dictate certain architectural parameters. Moreover,
separate
wheelchair lifts may be impossible to iniplenlent in hallways or other narrow
environments.
In an attempt to address some of the concerns of the separate vertical lift,
lifts
have been developed that cooperate with a staircase to provide a vertical lift
that fits
within a hallway or narrow environment. For example, U.S. Pat. No. 4,457,402
to Del
Vecchio et al. shows a lift that is disposed directly in front of a low rise
staircase that
extends from a lower surface to an upper surface. The lift provides vertical
transport of
wheelchairs from the lower surface to the level of the upper surface. When the
lift rises,
the stairs collapse upward to form a bridge platform that allows travel from
the lift
platform over the area normally occupied by the staircase to the destination
upper
surface.
Another proposed design of a lift that may be located in a na--row
environinent is
found in U.S. Pat. No. 5,234,078 to Smith. In the Smith patent, a lift
platform is located
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on the upper surface directly behind the ascending stairs. In other words, the
lift platform
forms a portion of the upper surface. The lift platform provides transport
between the
upper surface and the lower surface through vertical movement. When the lift
platform
lowers to the level of the lower surface, the stairs collapse so that they too
are
substantially on the level of the lower surface. Wlien the lift platforms
rises to the level
of the upper surface, the stairs reconfigure into a staircase.
A drawback of the designs found in the Del Vecchio et al. and Smith patents
discussed above is that they require space equivalent to the area of the lift
platforni either
completely in front of or completely behind the staircase. In some cases, such
area is not
available. Moreover, because the lift platform is located completely outside
the footprint
of the staircase, the lift platform creates a potentially displeasing
architectural
discontinuity with the surface at which it normally rests while not in
operation. For
example, as shown in FIG. I of the Smith patent, the lift structure reduires
special wall
and f7ooi- structures that create visible discontinuities along the floor and
wall. Likewise.
the lift shown in the Del Vecchio et al. patent, undesirable creates a piainly
visible
discontinuity along the intersection of the platform and lower (ground)
surface. Such
discontinuities signifieantly affect the appearance of an architectural
structure.
These issues were addressed by Storm in US Patent No. 5,937,971, in which a
rotating rail system is used to create, in one configuration, a flat
platforni, which can be
moved up or down, and in a second coni-iguration, an angled stairway. While
this design
provided a convertible lift mechanism that could be fitted within a snialler
space than the
Del Vecchio or Smith patents, it's rail system provides poor support for the
piatfo~rm,
and requires a complex system for movement of tlie rails and/or platform, and
is not
readily convertible for providing staircases of different heights. As such,
each must be
custom design for a particular location, or the building must be
architecturally modified
to nieet the design parameters of a standard staircase. Further, there is no
apparent
mechanism for adjustment of the stair height to conlply with various local
building
regulations. or the like.
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As such, there continues to exists a need, therefore, for a improved lift
structure
which is convertible from stairs to a moving platform, in order to provide
access between
a lower surface and an upper stirface. The design must continue to provide a
convertible
lift assembly that has reduced impact on the architectural and/or design
aspects of a
structure, and which nlay be employed in structures with space constraints.
Summary of the Invention
Accordingly, it is a principal advantage of the present invention to provide a
convertible lift assembly that partially or fully meets the goals and
objectives set out
hereinabove. These advantages, as well as other objects and goals inherent
thereto, are at
least partially or fully provided by the convertible lift assembly of the
present invention,
as set out liereinbelow.
In particular, the present invention fulfills the above need, as well as
others, by
providing a convertible lift assembly that provides a raisable frame that
nloves within a
space delined by two moveable side panels. When the side panels are moved
towards
one another, they provide resting points, in a stair-like shape, that eacll
collect one of a
series of flat stair panels that act as steps when the raisable frame is
lowered. When the
raisable frame is raised, it again collects the stair panels fcoili the
resting points, so that
they provide a horizontally flat platform.
When the side panels are moved away from each other, the raisable frame can be
raised and lowered witllout the stair panels meeting with their respective
resting points.
As a result, the flat platform remains intact as a flat platform as the
raisable frame is
raised and lowered.
Using this configuration provides a flat platform that does not need to be
implemented as a totally separate structure that both occupies additional
space and
impinges upon the architectural integrity of a structure. Instead, the
convertible lift
assembly of the present invention includes a flat, raisable platform that
occupies the
space that is otherwise occupied by the staircase, and therefore requires
little or no
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additional space.
Accordingly, in one embodiment, the present invention provides a convertible
lift assembly comprising;
a raisable frame which can be moved between a raised and lowered position;
a flat platform resting on said raisable fi=ame wlien said raisable frame is
in said
raised position, and wherein said flat platform comprises at least two stair
panels;
a first side panel and a second side panel, with at least one of said first or
second
side panels being inoveable between an extended position, to a contracted
position, by
movement of at least one side panel towards or away from said second side
panel;
a first motive device for nlovement of said raisable frame;
a second motive device for movement of at least one side panel;
a support structure for supporting said raisable frame, said side panels and
said
first and second motive devices; and,
a plurality of resting points on said side panels on which said stair panels
rest
w11en said raisable platform is lowered while said side panels are in said
contracted
position,
wherein said stair panels have a length which is less than the distance
between
corresponding resting points on said side panels when said side panels are in
said
extended position, and a length which is greater than the distance between
coi7-esponding
resting points on said side panels when said side panels are in said
contracted position.
Preferably both side panels are each movable towards or away from one another.
In operation, the essentially flat stair panels rest on the raisable frame in
an
essentially horizontally flat platform configuration, when the side panels are
in their
extended position. In this configuration, the raisable frame can be raised and
lowered and
the staii- panels will remain flat on the raisable frame since they do not
interact with the
side panels.
However, when the raisable frame is in its raised position, at least one, and
more
preferably both, side panels can be moved towards each other in order to be
positioned in
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a contracted position. In this position, the raisable frame is still able to
be lowered
between the side panels, but the stair panels will be caught by, and come to
rest on, the
resting points that are provided on the side panels. This prevents the stair
panel from
being lowered further. As such, the stair panel will beconle separated from
the raisable
fi=ame. When the raisable frame is completely lowered, one or more stair
panels will
remain on the side panel resting points in a stair-like configuration.
Tllc stairs can then be used in a norinal fashion wllile in this
configuration.
To convert the stair configuration back to a platforni configuration, the
raisable
frame is moved to a raised position in order to collect all of the stair
panels off of their
resting points, and again establish an essentially flat horizontal platfornl.
Witli the stair
panels off of the side panels, the side panels can then be returned to their
extended
position. The platform can then be used as previously described.
The raisable platform and moveable side panels are moved by an appropriate
tirst
or second motive forces. This is typically achieved through the use of at
least one electric
motor, although other motorized power sources, as motive forces, can be
utilized, as will
be clear to those skilled in the art.
Brief Description of the Drawings
Embodiments of this invention will now be described by way of example only in
association with the accompanying drawings in which:
Figure I is a perspective view of an embodiment of the present invention
wherein
it is in a raised platform configuration;
Figure 2 is a side view of a side panel used in the embodiment of Fig. 1;
Figure 3 is a. perspective view of the raisable frame together witli cut-away
view
of the stair panels;
Figure 4A to Figure 4D are a series of front views showing the movement of the
side panels and the raisable frame;
Figure 5 is a pei-spective view of the enlbodiment of Fig. 1 in a stair
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configuration;
Figure 6 is a front view of an alternative arrangement of the stair panels;
and
Figures 7A and 7B shown a ramp section fitted to the front of the frame.
Detailed Description of the Preferred Embodiments
The novel features which are believed to be characteristic of the present
invention, as to its structure, organization, use and niethod of operation,
together with
ftn-ther objectives and advantages thereof, will be better understood from the
following
drawings in which a presently preferred embodinient of the invention will now
be
illustrated by way of exanlple only. In the drawings, like reference numerals
depict like
elements.
It is expressly understood. however, that the drawings are for the purpose of
illustration and description only and are not intended as a definition of the
limits of the
invention.
Referring to Figure 1, a convertible lift assembly 10 is shown liaving a base
16,
two side modules 12 and two end modules 14, which are located on eitlier side
of base
16. Between end modules 14 is a stationary platform 28, and between side
modules 12
are a series of essentially flat stair panels 20, 22, 24 and 26 which in this
configuration
form a flat platform level with, and adjacent to stationary platform 28.
Panels 20. 22. 24
and 26 all rest on a frame 40. whicll frame 40 is capable of movement up or
down in
response from input fi-om either of controllers 60. On the interior side of
side nlodules 12
is a niovable side panel 18 having stair panel resting points 30, 3134 and 36,
as shown
in Figure 2 wllich is a side view of one side panel 18. The side panel 18 on
the opposite
side of assembly 10 will be a mirror image of this side panel.
Rcsting points 30, 32, 34 and 36 correspond with, and are positioned to
operatively mate with stair panels 20, 22, 24 and 26 respectively. Resting
points 30, 32,
34 and 36 are T-shaped and can be bolted to side panel 18 in the appropriate
location,
using bolt holes 38, to provide the desired stair height and/or location. A
number of bolt
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holes 38 are provided for each resting point, and these bolt holes 38, for a
particular
resting point, are vertically aligned so that they, and the respective resting
point, will be
positioned in the same relative position with respect to the stair panel.
Other sliapes and sizes for the resting points can be used, such as
rectangular.
square, triangular, or circular can be used to fit into a corresponding tlat,
triangular or
circula-- portion at the edge of the stair panels. Also, the resting points
can be a collection
of pins extending from the side panels. However, the T-shaped configuration is
a
preferred arrangement since it provides adequate strength properties, together
with ease
of attaclunent.
Further, while side panels 18 are preferably solid panels, they can be
replaced
with a frame structure that nioves the resting points closer together or apart
as necessary.
In an extreme variation, side panels 18 can be a series of solenoids that
merely niove
resting points 30, 32, 34 and 36 to their contracted or extended position.
However, for
strengtli and safety considerations, the sold panel configuration shown in
Figure 2 is
preferred.
It will be noted that convertible lift assembly 10 is shown with 4 movable
stair
panels, liowever, those skilled in the art will readily appreciate that any
number of
movable stair panels can be provided in order to produce the desired number of
stairs,
wlien the assembly is used in the stair configuration. Preferably, the number
of stairs
provided is between I and 10, and more preferably between 2 and 5.
Also, the present design is adaptable to provide a reduced number of stairs in
configurations wherein fewer stairs are required. For example, resting points
30 and 32
inight be removed altogetlier, and resting points 34 and 36 lowered to provide
a two stair
configuration. During installation of assembly 10, stationary platform 28
would be
lowered as necessary to be adjacent to pane126 when it was resting on frame 40
in the
raised position.
Frame 40 is shown in Figure 3 comprising 2 side rails 42, with 3 cross members
44, 46 and 48. In this design, frame 40 is narrower than the width of stair
panels 20, 22.
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24 and 26 for the correct operation of the device. 'I,he design of frame 40
can vary
depending on the intended application, or the like. For example, fraine 40 can
be
manufaetured wider than shown in the drawinus, and having gaps, channels,
spaces or
the like, through which the various resting points can pass as the frame is
raised oi-
lowered.
Franie 40 is connected to a motor (not shown) capable of raising or lowering
the
fi-ame with the additional weiglit from, or that has been placed on, stair
panels 20, 22, 24
and 26. The motor can be, for example, placed between end modules 14, and
under
stationary platforin 28, and can be operatively connected to frame 40 by
attachment to.
for example franle cross meinber 48, or the like.
The connection of frame 40 to the motor can be achieved in a number of
dii'ferent
fashions known to those skilled in the art, but the connection must
sufficiently strong
than fi=ame 40 can be raised and lowered in an essentially tlat orientation,
without
excessive bending of frame 40.
The operational details of the various moving components of convertible lift
assembly 10 arc shown in Figures 4A to 4D.
In Figure 4A, all of the stair panels 20, 22, 24 and 26 are resting on fi-anle
40 in a
raised position which provides a flat platform adjacent to stationary platform
28 so that a
user of the device, can walk out on to, or niove a wheelchair, for example. to
a position
resting of stair panels 20, 22, 24 and 26.
Side panels 18 are in an extended position wherein they are positioned within
side modules 12. Resting points 30, 32. 34 and 36 can be seen, but it is to be
noted that
the distance between corresponding resting points 30, 32, 34 and 36 is greater
than the
length of stair panels 20, 22, 24 and 26.
From this configuration, frame 40 can be lowered, in response to a command
from either upper or lower controller 60 to the position shown in Figure 4B
wherein
frame 40 is essentially resting on base 16 so that stair panels 20, 22, 24 and
26 are
essentially level with the ground, or level with a small ramp (not shown) to
facilitate
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entry and/or exit from assenlbly 10.
In use, in the configtu ation, the user is able to, for example, roll a
wheelchair
onto the platform formed by stair panels 20, 22, 24 and 26, and the platform
can be
raised oi- lowered, depending on the desired action. The platform will be
raised or
lowered as a flat platform, and the user will be able to exit the assembly in
the raised or
lowered confi'~uration.
Various safety features (not shown) can be provided such as side bar, hand
rails,
end bars, or the like to prevent accidental movement of the user as the
platform is raised
or lowered, or to prevent the user from accidentally rolling or falling over
the end of the
raised platform.
To convert to the stair configuration, raisable frame 40 and all stair panels
are
moved to a raised position. Side panels 18 are then moved, by a motorized
device for
example, to a contracted position wherein they protrude inwardly from side
nlodules 12.
In the contracted position, the distance between most of side panels 18 is
greater than the
length of stair panels 20, 22. 24 and 26. However, the distance between
corresponding
resting points 30, 32, 34 and 36 is now less than the length of stair panels
20, 22, 24 and
26. Further, the width of frame 40 is less than the distance between resting
points 30, 32,
34 and 36 so that frame 40 is able to move up and down without interference
from any
resting points 30. 32, 34 and 36.
Once side panels 18 are in the contracted position, frame 40 is lowei-ed. As
it
moves to the lower position, stair panels 20, 22, 24 and 26 come to rest on
their
corresponding resting points, i.e. resting points 30, 32, 34 and 36
respcctively. When
frame 40 reaclies ground level, all of the stair panels are in position, on
their resting
points, in a stair configuration. This is best seen in Figure 5. When left in
this position,
anyone wishing to move fi=om one level to another, can use the convertible
lift assembly
10 as a nornlal set of stair.
To convei-t the stair configuration back to a platform configuration, frame 40
is
raised using a motorized power source aaid as it is raised, collects stair
panels 20, 22. 24
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and 26, in that order, in order to re-create the flat platform resting on
frame 40. Once
fi-anie 40 is in its raised position, side panels 18 are moved to tlleir
extended position so
that frame 40 can be raised and lowered and stair panels 20, 22, 24 and 26
will again
remain on frame 40. The essentially flat horizontal platform can then be used
as
previously described.
While not shown in detail, it will be clear to those skilled in the art that
other
safety features can be incorporated into the design of the present invention.
These
include, for example, safety interlocks to prevent side panels 18 from being
moved
unless fi-ame 40 is in a raised position. Additionally, locking mechanisms
such as
protruding pins on resting points 30, 32, 34 and 36 can be provided that
extend into
corresponding holes on stair panels 20, 22, 24 and 26 so as to prevent the
stair panels
from moving. Electronic sensors can be provided to ensure that the pins are in
place
when the convertible lift assembly is in the stair configuration.
Other safety features can be incorporated as desired by the opei-ator.
In Figure 6, an alternative arrangenlent for the stair panels is provided and
these
panels are designated as panels 20A and 22A. These stair panels are
essentially flat in
their central area, but have a raised side section 50 which rests on the
resting points.
However, wlien the stair panels 20A and the like are all positioned on frame
40 in the
platform configuration, raised side sections 50 provide a side ledge to
prevent accidental
movement of a user, or a wheelchair, or the like, off the side of the
platform.
Also, other design features, such as face plates 62 can be provided which are
attached to the front surface of any or all stairs panels to reduce access to
the area ilnder
the stairs, or to provide a cleaner appearance to while in the stair
configuration. These
face plates 62 are positioned to as to side into frame 40 as it is being
raised or lowered,
and not otherwise interfere with the operation of the convertible lift
assembly.
Further frame 40 can be equipped with a movable ramp section 64, shown in
Figure 7A which can be moved, by a suitable additional motive force, to a
raised
position to prevent a user from accidentally moving off of the platform, when
the
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platform is above ground level, and moved to a lowered position shown in
Figure 7B
whicll will act as a small ramp, to facilitate entry of a wheelchair, for
example. onto the
platform when the frame 40 is in a lowered position.
In a fiirther aspect, the present invention also provides an improved method
for
lifting a person or an object, such as a wlieelchair or other personal
vehicle, from a lower
surface to an upper surface, usin, the device of the present invention.
As discussed above, it is to be noted that the prior art solutions requii-ed a
substantial amount of additional space to provide facilities for non-
ambulatory persons.
Not only were the additional space requirements difficult and some times
impossible to
accommodate at all, even when aceomniodation was possible, the prior art
devices often
required alteration of the architectural structtu=e of a facility. By
contrast, the method and
apparatus of the present invention employs the same footprint for both the
stairs and the
alternative facilities by converting one or more stairs to a lift platfornl.
The resulting
structure has the advantage of requiring substantially less space.
It is also to be noted that the motorized power sources and the linkages used
to
niove the side panels or the raisable frame have not been detailed in the
present
application. While the source of motorized power sources in the above
described
embodiment is preferably one or more electric motors, other fornls of motive
power may
be employed. In particular, for lifting the frame, these include systems such
as a
hydraulic lift system power source, a pneumatic piston system power source,
and the
like. Also. combinations of any of these motorized power sources can be
utilized, or,
through the selection of appropriate linkages and the like, a single motor can
act as both
the first and second motive power sources. However, it is clear that those of
ordinary
skill in the art may readily determine the appropriate type and number of
motorized
power source, and the appropriated linkage configurations required for a
particular
implementation.
Thus, it is apparent that there has been provided, in accordance with the
present
invention, a convertible lift assembly which ftilly satisfies the goals,
objects, and
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advantages set forth hereinbefore. Therefore, having described specific
etnbodiments of
the present invention, it will be understood that alternatives, modifications
and variations
thereof nlay be suggested to those skilled in the art, and that it is intended
that the presetit
specification embrace all such alternatives, modifications and variations as
fall within
the scope of the appended claims.
Additionally, for clarity and unless otherwise stated, the word "comprise" and
variations of the word such as "comprising" and "cotnprises'", wllen used in
the
description and claims of the present specification, is not intended to
exclude other
additives, components, integers or steps.
Moreover, the words "substantially" or "essentially", when used wit11 an
ad.jectivc
or adverb is intended to enhance the scope of the particular characteristic;
e.g.,
"substantially planar", or "essentially planar" is intended to mean planar,
nearly planar
and/or exhibiting characteristics associated witll a planar elenlent.
Also, wliile this discussion has addressed prior art known to the inventor, it
is not
an admission that all art discussed is citable against the present
application.
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