U.S. patent application number 10/455879 was filed with the patent office on 2004-02-12 for single arm wheelchair lift.
This patent application is currently assigned to Ricon Corporation. Invention is credited to Reynolds, Ray.
Application Number | 20040028513 10/455879 |
Document ID | / |
Family ID | 31498485 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040028513 |
Kind Code |
A1 |
Reynolds, Ray |
February 12, 2004 |
Single arm wheelchair lift
Abstract
A wheelchair lift configured to be foldable into quadrants by a
two-step folding process, wherein the first step folds the platform
assembly crosswise and the second step folds the platform assembly
in the lengthwise direction. To facilitate the folding, the
platform assembly includes first and second inner platforms, and
first and second outer platforms. In the first step of the folding
process, the first and second inner platforms fold with respect to
the first and second outer platforms. In the second step of the
folding process, the second inner and outer platforms fold with
respect to the first inner and outer platforms.
Inventors: |
Reynolds, Ray; (Hollywood,
CA) |
Correspondence
Address: |
JEFFER, MANGELS, BUTLER & MARMARO, LLP
1900 AVENUE OF THE STARS, 7TH FLOOR
LOS ANGELES
CA
90067
US
|
Assignee: |
Ricon Corporation
Panorama City
CA
91402
|
Family ID: |
31498485 |
Appl. No.: |
10/455879 |
Filed: |
June 6, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60386338 |
Jun 6, 2002 |
|
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|
Current U.S.
Class: |
414/546 |
Current CPC
Class: |
A61G 3/062 20130101;
F16H 35/10 20130101 |
Class at
Publication: |
414/546 |
International
Class: |
B60P 001/00 |
Claims
What is claimed is:
1. A wheelchair lift for use in conjunction with a vehicle, the
wheelchair lift comprising: a platform assembly having a first
inner platform, a second inner platform, a first outer platform,
and a second outer platform; wherein the first inner platform is
pivotally connected to the second inner platform; wherein the first
outer platform is pivotally connected to the second outer platform;
wherein the first and second inner platforms are pivotally
connected to the first and second outer platforms; and a storage
configuration wherein the first and second inner platforms fold
crosswise with respect to the first and second outer platforms, and
the second inner platform and second outer platform fold lengthwise
with respect to the first inner platform and first outer
platform.
2. A wheelchair lift having a platform assembly foldable in a first
crosswise fold and in a second lengthwise fold.
3. The wheelchair lift of claim 2 wherein the first crosswise fold
and second lengthwise fold are not parallel.
4. The wheelchair lift of claim 2 wherein the first crosswise fold
and second lengthwise fold are perpendicular.
5. A method of folding the platform assembly of a wheelchair lift,
the method comprising the steps of: folding the platform assembly
crosswise; and folding the platform assembly lengthwise.
6. The method of claim 5 wherein the step of folding the platform
assembly lengthwise follows the step of folding the platform
assembly crosswise.
7. A wheelchair lift for use in conjunction with a vehicle, the
wheelchair lift comprising: a platform assembly having a first
inner platform, a second inner platform, a first outer platform,
and a second outer platform; a first fold actuating assembly
configured to pivot the first and second inner platforms with
respect to the first and second outer platforms; and a second fold
actuating assembly configured to pivot the second inner and outer
platforms with respect to the first inner and outer platforms.
8. The wheelchair lift of claim 7 wherein the first fold actuating
assembly comprises: a linking arm pivotally connected to the
platform assembly at a first connection point; a platform actuator
bar connected to the platform assembly at a second connection
point, the platform actuator bar configured to exert force on the
platform assembly at a second connection point in a manner that
causes the platform assembly to rotate about the first connection
point.
9. The wheelchair lift of claim 8 wherein the fold actuating
assembly further comprises a fold mechanism cam engageable with a
cam follower on the platform actuator bar, wherein the fold
mechanism cam contacts the cam follower and exerts force on the
platform actuator bar.
10. The wheelchair lift of claim 7 wherein the second fold
actuating assembly comprises a piston and cylinder assembly.
11. The wheelchair lift of claim 10 further comprising a power
actuating system wherein the piston and cylinder assembly is in
operative communication with the power actuating system.
12. A wheelchair lift for use in conjunction with a vehicle, the
wheelchair lift comprising: a platform assembly having a first
inner platform, a second inner platform, a first outer platform,
and a second outer platform; a first fold actuating assembly
configured to pivot the first and second inner platforms with
respect to the first and second outer platforms the first fold
actuating assembly comprising a linking arm pivotally connected to
the platform assembly at a first connection point, a platform
actuator bar connected to the platform assembly at a second
connection point, the platform actuator bar configured to exert
force on the platform assembly at a second connection point in a
manner that causes the platform assembly to rotate about the first
connection point; and a second fold actuating assembly configured
to pivot the second inner and outer platforms with respect to the
first inner and outer platforms, wherein the second fold actuating
assembly comprises a piston and cylinder assembly.
13. A wheelchair lift for use in conjunction with a vehicle, the
wheelchair lift comprising: a platform assembly having a first
inner platform, a second inner platform, a first outer platform,
and a second outer platform; a first hinge pivotally connecting the
first inner platform to the second inner platform, the first hinge
having a first pivot axis; a second hinge pivotally connecting the
first and second inner platforms to the first and second outer
platforms, the second hinge having a second pivot axis; a third
hinge pivotally connecting the first outer platform to the second
outer platform having a third pivot axis; and a storage
configuration wherein the first and second inner platforms fold
crosswise with respect to the first and second outer platforms
about the first pivot axis, and the second inner platform folds
lengthwise with respect to the first inner platform about the
second pivot axis, and the second outer platform folds lengthwise
with respect to the first outer platform about a third pivot axis,
wherein the second and third pivot axes are colinear.
14. The wheelchair lift of claim 13 wherein the third pivot axis is
spaced apart from the third hinge.
15. The wheelchair lift of claim 13 wherein the third hinge
comprises: a first block hinge; a second block hinge; and a
plurality of link members connecting the first block hinge to the
second block hinge, each link member having a first end, a second
end and a common portion, the first end of each link member
pivotally connected to one of the first and second block hinges,
the second end of each link member slidably engaged to the other of
said first and second block hinges, and the common portions of the
plurality of link members pivotally connected to each other.
16. The wheelchair lift of claim 15 wherein the third hinge
comprises a first link member pivotally connected to the first
block hinge and slidably engaged with the second block hinge, and a
second link member adjacent the first link member, the second link
member pivotally connected to the second block hinge and slidable
engaged with the first block hinge.
17. The wheelchair lift of claim 16 wherein the first and second
block hinges each comprises a slot therein, the slot having an
outer side and an inner side, the third hinge further comprising a
contracted configuration wherein the first block hinge is adjacent
the second block hinge and wherein the second end of the first link
member is positioned at the outer side of the slot in the second
hinge block and the second end of the second link member is
positioned at the outer side of slot in the first hinge block.
18. The wheelchair lift of claim 13 wherein the second hinge is a
piano hinge.
19. A floating pivot hinge having a pivot axis spaced apart
therefrom, the floating pivot hinge comprising: a first block
hinge; a second block hinge; and a plurality of link members
connecting the first block hinge to the second block hinge, each
link member having a first end, a second end and a common portion,
the first end of each link member pivotally connected to one of the
first and second block hinges, the second end of each link member
slidably engaged to the other of said first and second block
hinges, and the common portions of the plurality of link members
pivotally connected to each other.
20. A floating pivot hinge having a pivot axis spaced apart
therefrom, the floating pivot hinge comprising: a first block
hinge; a second block hinge; a first link member pivotally
connected to the first block hinge and slidably engaged with the
second block hinge; and a second link member adjacent the first
link member, the second link member pivotally connected to the
second block hinge and slidably engaged with the first block
hinge.
21. The floating pivot hinge of claim 20 wherein each of the first
and second block hinges comprise a slot for slidably engaging the
link members.
22. The floating pivot hinge of claim 20 wherein each of the first
and second link members comprise a common portion and are pivotally
connected at the common portion.
23. A floating pivot hinge having a pivot axis spaced apart
therefrom, the floating pivot hinge comprising: a first block hinge
and a second block hinge, each of the first and second block hinges
having a slot therein; a first link member pivotally connected to
the first block hinge and slidably engaged with the slot of the
second block hinge; a second link member adjacent the first link
member, the second link member pivotally connected to the second
block hinge and slidably engaged with the slot of the first block
hinge; and wherein the first and second link members each have a
common portion and are pivotally connected to each other at the
common portion.
24. A wheelchair lift comprising a platform assembly, the platform
assembly having a front end, a first side and a second side
opposite the first side, wherein the platform assembly is
configured to allow a wheelchair access thereon from the front end,
first side and the second side.
25. A wheelchair lift, comprising: a power actuating system; a
platform assembly having a first end; an automatic platform tilt
mechanism operatively connected to the power actuating system,
wherein the automatic platform tilt mechanism is configured to tilt
the first end of the platform assembly.
26. A method of operating a wheelchair lift, comprising the steps
of: providing a power actuating system, a platform assembly having
a first end, and an automatic platform tilt mechanism; tilting the
first end of the platform assembly upward; and lifting the platform
assembly; wherein the power actuating source provides power for
both tilting and lifting the platform assembly, wherein lifting the
platform assembly is sequenced immediately after the tilting and
requires no intervening action.
27. A method of operating a wheelchair lift, comprising the steps
of: providing a power actuating system, a platform assembly having
a first end, and an automatic platform tilt mechanism; tilting the
first end of the platform assembly downward; and lowering the
platform assembly; wherein the power actuating source provides
power for both tilting and lowering the platform assembly, wherein
the tilting downward is sequenced immediately after lowering the
platform assembly and requires no intervening action.
28. A method of operating a wheelchair lift, comprising the steps
of: providing a power actuating system, a platform assembly having
a first end, and an automatic platform tilt mechanism; lowering the
platform assembly; raising the platform assembly; wherein the
platform tilt mechanism tilts the platform downward immediately
after lowering the platform assembly to the ground level, without
any intervening action by the user; wherein the platform tilt
mechanism tilts the platform assembly upward immediately before
raising the platform assembly, without any intervening action by
the user; wherein the power actuating source provides power for the
tilting, raising and lowering of the platform assembly.
29. The method of claim 28 wherein the platform tilt mechanism
comprises: a linking arm pivotally connected to the platform
assembly at a first connection point; and a platform actuator bar
connected to the platform assembly at a second connection point,
the platform actuator bar configured to exert force on the platform
assembly at a second connection point in a manner that causes the
platform assembly to rotate about the first connection point.
30. The method of claim 29 wherein the platform tilt mechanism
further comprises a lift mechanism cam engageable with a cam
follower on the platform actuator bar, wherein the fold mechanism
cam contacts the cam follower and exerts force on the platform
actuator bar.
31. A platform tilt mechanism for tilting the platform assembly of
a wheelchair lift, the tilt mechanism comprising: a linking arm
pivotally connected to the platform assembly at a first connection
point; and a platform actuator bar connected to the platform
assembly at a second connection point, the platform actuator bar
configured to exert force on the platform assembly at a second
connection point in a manner that causes the platform assembly to
rotate about the first connection point.
32. The tilt mechanism of claim 31 wherein the platform tilt
mechanism further comprises a lift mechanism cam engageable with a
cam follower on the platform actuator bar, wherein the fold
mechanism cam contacts the cam follower and exerts force on the
platform actuator bar.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
Patent Application No. 60/386,339 filed on Jun. 6, 2002, the
contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to wheelchair
platform lift assemblies, and more particularly, to a wheelchair
lift that folds into a compact state.
BACKGROUND OF THE INVENTION
[0003] There has been an increasing interest in developing
automated devices to facilitate the mobility of wheelchair users.
Various platform devices, such as lifts and ramps, have been
proposed to assist wheelchair users in getting in and out of
vehicles. To ensure the safety of the wheelchair user, the platform
device must be large enough and sufficiently durable to support the
wheelchair and a person thereon during the loading and unloading
process. As a result, a typical platform device can be four to five
feet long.
[0004] A problem with lengthy and bulky platforms is that it can be
difficult to fit the platform within a standard-size vehicle. When
bulky platforms are installed in vehicles, the entry way may have
to be widened and components of the vehicle may have to be
rearranged to accommodate the sizable platform. To avoid the
inconvenience of installing a sizable platform, there is a need for
new passenger platforms that have a compact configuration when
installed in a vehicle.
[0005] Another problem with bulky wheelchair platforms is that when
the platform is installed on one side of the vehicle, the
suspension of the vehicle rolls to the side at which the wheelchair
platform is installed. Consequently, the platform rolls outboard,
i.e., tilts away from the vehicle in a downward slope. The rolling
of the vehicle suspension creates an uncomfortable situation for
the rider because the platform is no longer horizontal, giving the
rider the impression of being in a less safe position while
suspended over the ground.
[0006] One known method of resolving the tilting problem is
allowing the user to tilt the platform toward the vehicle to
correct for the tilting of the platform away from the vehicle
caused by the rolling of the suspension. The tilt correction
mechanism is a secondary operation that requires a separate
actuator and a separate control. To operate the tilt correction
mechanism, the platform must first be lifted off of the ground. The
user then uses a separate control switch to tilt the platform to
compensate for the roll of the vehicle. Once the user has reached a
comfortable tilt position, the main control switch is activated to
proceed with the motion of the platform into or out of the vehicle.
The disadvantage of this system is that a separate actuator and
control switch is required for the tilt correction mechanism,
complicating the mechanical structure and operation of the platform
device.
[0007] Another known solution to the tilting problem is to adjust
the platform so that it is permanently tilted towards the vehicle,
thus accommodating for the tilt away from the vehicle caused by the
rolling of the suspension. The disadvantage of permanently tilting
the platform towards the vehicle is that, if the platform is
adjusted with too much tilt, the front of the platform does not
rest on the ground but remains tilted upwards, above the ground.
This problem is especially common on roads with a heavy crown, such
as a road with deep gutters.
[0008] Accordingly, there is a need to provide a platform device
that levels to a comfortable tilt toward the vehicle without
requiring a secondary tilt correction mechanism with a separate
control switch.
SUMMARY OF THE INVENTION
[0009] A wheelchair lift configured to be foldable into quadrants
by a two-step folding process, wherein the first step folds the
platform assembly crosswise and the second step folds the platform
assembly lengthwise. To facilitate the folding, the platform
assembly includes first and second inner platforms, and first and
second outer platforms. In the first step of the folding process,
the first and second inner platforms fold with respect to the first
and second outer platforms. In the second step of the folding
process, the second inner and outer platforms fold with respect to
the first inner and outer platforms. The wheelchair lift preferably
includes a storage configuration wherein the two-step folding
process has been completed.
[0010] The platforms are pivotally connected by hinges. In a
preferred embodiment of the invention, the first and second inner
platforms are connected to the first and second outer platforms by
a first hinge, which pivots about a first axis. The first inner
platform is connected to the second inner platform by a second
hinge that pivots about a second axis. The first outer platform is
connected to the second outer platform by a third hinge that pivots
about a third axis. To complete the second fold of the two-step
folding process, the second axis must be aligned with the third
axis. Accordingly, the third hinge is configured to have a pivot
axis that is spaced apart from the third hinge, and co-linear with
the pivot axis of the second hinge.
[0011] To facilitate the folding, the wheelchair lift includes a
first fold actuating assembly, to fold the platform assembly
crosswise, and a second fold actuating assembly, to fold the
platform assembly lengthwise. The first fold actuating assembly
includes a linking arm pivotally connected to the platform assembly
at a second connection point and a platform actuator bar connected
to the platform assembly at a second connection point, spaced apart
from the first connection point. The first fold actuating assembly
folds the platform crosswise by exerting force on the platform
assembly at a second connection point in a manner that causes the
platform assembly to rotate about the first connection point. The
exertion of pressure is preferably accomplished by the engagement
of a cam with a cam follower on the platform actuator bar. The
second fold actuating mechanism is preferably an electrical
actuator, and more preferably, an actuator as described in U.S.
Provisional Patent Application No. 60/386,338 filed Jun. 6, 2002
and Ser. No. ______ for Clutch-Driven Limited Force Actuator filed
concurrently herewith, the contents of which are incorporated
herein by reference. However, it is within the scope of the present
invention to utilize a piston and cylinder assembly or other known
actuators to cause the second side of the platform assembly to
pivot with respect to the first side.
[0012] The wheelchair lift of the present invention preferably
includes a mechanism that causes the platform assembly to tilt
upward immediately prior to the lifting of the platform assembly,
and to tilt downward immediately after the lowering of the platform
assembly. The tilting of the platform assembly is accomplished by
using the same actuating power system used to lower and raise the
platform and does not require a separate actuator or a separate
control switch. In a preferred embodiment of the invention, the
tilting upward immediately prior to the raising of the platform and
the tilting downward is sequenced immediately after the lowering of
the platform without requiring any intervening action on the part
of the lift user.
[0013] Other objects, features and advantages of the present
invention will become apparent to those skilled in the art from the
following detailed description. It is to be understood, however,
that the detailed description and specific examples, while
indicating preferred embodiments of the present invention, are
given by way of illustration and not limitation. Many changes and
modifications within the scope of the present invention may be made
without departing from the spirit thereof, and the invention
includes all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention may be more readily understood by referring to
the accompanying drawings in which:
[0015] FIG. 1 depicts a perspective view of a preferred embodiment
of the wheelchair lift of the present invention;
[0016] FIG. 2 depicts a top plan view of a preferred embodiment of
the wheelchair lift of the present invention;
[0017] FIG. 3 depicts an elevational side view of a preferred
embodiment of the wheelchair lift of the present invention;
[0018] FIG. 4 depicts an elevational front view of a preferred
embodiment of the wheelchair lift of the present invention;
[0019] FIG. 5 depicts a partial cross-sectional side view of a
preferred embodiment of the wheelchair lift of the present
invention showing the platform assembly tilted upward;
[0020] FIG. 5A is an enlarged view of the platform tilt mechanism
of FIG. 5;
[0021] FIG. 6 depicts a partial cross-section side view of a
preferred embodiment of the wheelchair lift of the present
invention showing the platform assembly tilted downward;
[0022] FIG. 6A is an enlarged view of the platform tilt mechanism
of FIG. 6;
[0023] FIG. 7 is a top plan view of a preferred embodiment of the
wheelchair lift of the present invention in an entry level
configuration;
[0024] FIG. 8 is a perspective view of a preferred embodiment of
the wheel chair lift of the present invention showing the first
fold of the two-step folding process of the platform assembly;
[0025] FIG. 9 is a perspective view of a preferred embodiment of
the present invention showing the wheelchair lift upon completion
of the first fold;
[0026] FIGS. 10A-10C depict the folding process of the second fold
in the two-step folding process of the present invention;
[0027] FIG. 11 is a perspective view of a preferred embodiment of
the present invention showing the wheelchair lift upon completion
of the second fold;
[0028] FIG. 12 is an elevation front view of the folded wheelchair
lift shown in FIG. 11;
[0029] FIG. 13 is a top plan view of a preferred embodiment of the
floating pivot structural hinge of the present invention, shown in
a fully expanded position;
[0030] FIG. 14 is an exploded view of the floating pivot structural
hinge of FIG. 13;
[0031] FIG. 15 is a top plan view of the floating pivot structural
hinge of FIG. 13, shown in a contracted position;
[0032] FIG. 16 is a cross-section view of the floating pivot
structural hinge of FIG. 15 taken along line 16-16;
[0033] FIG. 17 is a partial cut-out perspective view of a preferred
embodiment of the floating pivot structural hinge, showing the link
members connected to the block hinges; and
[0034] FIG. 18 is an elevational side view of a preferred
embodiment of a floating pivot structural hinge of the present
invention.
[0035] Like numerals refer to like parts throughout the several
views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0036] A preferred embodiment of the single arm wheelchair lift 10
of the present invention is shown in FIGS. 1 through 4. The lift 10
is preferably installed inside a vehicle (not shown) near an
opening, such as a side door of the vehicle, to facilitate the
ingress and egress of a wheelchair and its occupant. The lift 10
can also be installed near the rear door or any other door of the
vehicle. The lift 10 is firmly secured on the doorway of the
vehicle by a mounting assembly 12. In a preferred embodiment of the
invention, the mounting assembly 12 includes support brackets 14
that extend through the vehicle floor to connect the lift to the
underside of the vehicle.
[0037] The mounting assembly 12 is preferably housed in a control
tower 16. The control tower 16 also houses the power actuating
mechanism 20 for actuating the lift from a folded, stowed
configuration (shown in FIG. 11) to an entry level configuration
(flush with the vehicle floor, shown in FIG. 3), to a ground level
configuration (shown in FIG. 1). For ease of operation, the power
actuating mechanism 20 can be powered by electrical, hydraulic or
pneumatic means, or other source of energy known to those skilled
in the art. For exemplary purposes, a hydraulic actuating system is
described herein. In a preferred embodiment of the invention, the
hydraulic actuating system includes a hydraulic pump, a hydraulic
power unit, and a piston and cylinder assembly 22 operatively
connected to the hydraulic pump and the hydraulic power unit.
[0038] The piston and cylinder assembly 22 is preferably installed
in a parallelogram actuating linkage structure 30 fixed to the
control tower 16. It is envisioned that the parallelogram actuating
linkage structure 30 can be replaced with other linkage structures
known in the art without departing from the scope and spirit of the
present invention. The linkage structure 30 preferably includes a
top actuating arm 32 and a bottom actuating arm 34 which are
located substantially parallel to each other. The first ends 36, 38
of the top and bottom actuating arms 32, 34 are pivotally connected
to the control tower 16. The second ends 42, 44 of the top and
bottom actuating arms 32, 34 are pivotally connected to a linking
arm 40. In a preferred embodiment of the invention, the linking arm
40 is vertically aligned.
[0039] When the piston and cylinder assembly 22 is extended, the
linkage structure 30 causes the linking arm 40 to move upwardly. It
is the upward motion of the linking arm 40 that move the lift 10 in
an upward direction. When the piston and cylinder assembly 22
retracts, the linkage structure causes the linking arm 40 to move
downwardly. It is the downward motion of the linking arm that
causes the lift to move toward the ground.
[0040] In a preferred embodiment of the invention, as best shown in
FIGS. 1 and 2, the platform assembly 50 of the lift includes first
and second rear platforms 52, 54 and first and second front
platforms 56, 58. The first and second rear platforms 52, 54 are
pivotally attached to each other along line A and the first and
second front platforms 56, 58 are also pivotally attached to each
other along line B. Furthermore, the rear platforms 52, 54 are
pivotally connected to the front platforms 56, 58 along line C.
Lines A and B are preferably co-linear when the platform assembly
is in a fully extended configuration. Line C is preferably
perpendicular to lines A and B. In a fully extended configuration,
the front and rear platforms 52, 54, 56, 58 collectively form the
surface on which the wheelchair is placed during transport between
the entry level and the ground level.
[0041] In the embodiment shown in FIGS. 1 and 2, rear bridge plates
60 are connected to the platform assembly 50. During transport
between the entry level and ground level configurations, the bridge
plates 60 are positioned in a vertical position with respect to the
platform assembly 50 to create a rear barrier for preventing a
wheelchair from rolling off the platform assembly. When the lift is
at the entry level configuration, as best shown in FIG. 3, the
bridge plates 60 move into a horizontal position such that the
bridge plates 60 are co-planar with the platform assembly 50 and
the vehicle floor. The bridge plates 60 provide a bridge from the
platform assembly to the vehicle to ensure safe ingress and egress
to the vehicle.
[0042] In addition to the bridge plates 60, the lift 10 of the
present invention preferably includes a pair of side barriers 62,
64 and front barriers 66. As shown in FIG. 1, during transport
between the entry level and ground level configurations, the side
and front barriers 62, 64, 66 are positioned substantially normal
to the platform assembly 50, to prevent a wheelchair from rolling
off the platform assembly. When the lift is at the ground level
configuration, as best shown in FIG. 6, the side and front barriers
62, 64, 66 move downward into a horizontal position such that the
barriers provide a smooth transition path for the wheelchair to
disembark from the platform assembly onto the ground or to embark
the platform assembly from the ground. The side and front barriers
62, 64, 66 are dimensioned such that when the side barriers are
down, the platform assembly 50 is accessible by a wheelchair from
three different sides. A wheelchair can enter or exit the platform
assembly from the left side, the right side or the front of the
platform assembly. In some instances, when the lift 10 is at ground
level, there may be an obstacle preventing access to the platform
assembly from the front. In these situations, it is convenient to
provide access to the platform assembly from the sides, in addition
to the access from the front. Also, the linking arm 40, as will be
described in further detail below, is positioned such that it does
not interfere with the movement of the side barrier 62 or a
wheelchair's access to the platform assembly from that side.
[0043] In a preferred embodiment of the present invention, the lift
10 includes an automatic platform tilt mechanism 70 to accommodate
the roll of the vehicle suspension. The weight of the wheelchair
lift installed on one side of the vehicle, together with the weight
of the wheelchair and its occupant when loaded thereon, can cause
the suspension of the vehicle to roll to one side. When the
suspension rolls, the platform assembly tilts downward, away from
the vehicle. Because the platform is no longer horizontal, a rider
may feel that he or she is not in a safe position. Accordingly, the
lift 10 of the present invention, preferably includes an automatic
platform tilt mechanism to automatically adjust for the roll of the
vehicle suspension.
[0044] The operation of the platform tilt mechanism 70 is best
described in reference to FIGS. 5, 5A, 6 and 6A. FIGS. 6 and 6A
depict the platform tilt mechanism 70 when the wheelchair lift is
at ground level in a tilted down position to facilitate the exit or
entry of a wheelchair. In this position, the piston and cylinder
assembly 22 is in a fully retracted configuration. The piston and
cylinder assembly is preferably pivotally connected to a main
platform actuator 72. The main platform actuator 72 is pivotally
connected to a first end 76 of a link platform actuator 74. The
second end 78 of the link platform actuator 74 is pivotally
connected to a lift mechanism cam 80.
[0045] During the tilting process, the lift mechanism cam 80
interacts with a cam follower 82. The cam follower 82 is preferably
attached to a first end 86 of the platform actuator bar 84. The
second end 88 of the platform actuator bar 84 is connected to the
platform assembly 50. In a preferred embodiment of the invention,
the second end 88 of the platform actuator bar 84 is connected to
the first front platform 56 at connection point 90. Connection
point 90 is preferably adjacent to line C (best shown in FIG. 2).
The linking arm 40 is also pivotally connected to the first front
platform 56 at connection point 92. Connection point 92 is
preferably spaced apart from connection point 90 and is farther
from line C than connection point 90.
[0046] As best shown in FIGS. 5 and 5A, as the piston and cylinder
assembly 22 extends in the direction E, the first end 76 of the
link platform actuator 74 moves in the same direction as the piston
and cylinder assembly. As the first end 76 moves in direction E,
the second end 78 moves in the opposite direction, causing the link
mechanism cam 80 to rotate. The link mechanism cam 80 exerts force
on the cam follower 82, which causes the platform actuator bar 84
to move in a downward direction. When forced downward, the platform
actuator bar 84 exerts force on the first front platform 56 at
connection point 90, causing the first and second front platforms
56, 58 to rotate about connection point 92. As the front platforms
56, 58 rotate about connection point 92, the front end 94 of the
platform assembly 50 tilts upward.
[0047] The platform tilt mechanism 70 is configured to tilt the
platform assembly 50 to the extent that it accommodates for the
roll of the vehicle suspension. The platform tilt mechanism 70 of
the present invention does not require a separate actuator system
or control switch. It utilizes the same power actuating mechanism
20 that operates the lift from a stowed configuration to an entry
level configuration, and to a ground level configuration. The tilt
mechanism 70 is simply an initial operation that is automatically
performed upon lifting and landing.
[0048] When the platform assembly 50 is lifted off the ground, the
tilt mechanism 70 tilts the platform assembly as described and the
main platform actuator 72 contacts the inner surface 46 of the
linking arm 40. Thereafter, the main platform actuator 72 can not
move any further, and as the piston and cylinder assembly 22
continues to expand, the tilting stops and the lifting of the
linking arm 40 commences. Thus, the wheelchair lift 10 of the
present invention automatically sequences the lifting operation to
commence upon completion of the tilting operation.
[0049] During the landing (or lowering) process, the sequencing
occurs in reverse order, i.e., the landing operation commences
first and when the platform assembly is at ground level, the
tilting operation commences to ensure that the front end 94 of the
platform assembly reaches the ground. During the lowering process,
when the lift 10 has arrived at ground level, as best shown in
FIGS. 6 and 6A, the piston and cylinder assembly 22 continues to
retract, causing the first end 76 of the link platform actuator 74
to move in the direction R. The link platform actuator 74 moves
away from the inner surface 46 of the linking arm 40. As the first
end 76 moves in direction R, the second end 78 moves in the
opposite direction E, causing the link mechanism cam 80 to rotate.
The link mechanism cam 80 rotates on the cam follower 82, which
causes the platform actuator bar 84 to move in an upward direction.
When the force of the cam 80 on the cam follower 82 is removed, the
platform actuator bar 84 lifts the first front platform 56 at
connection point 90, causing the first and second front platforms
56, 58 to rotate about connection point 92. As the front platforms
56, 58 rotate about connection point 92, the front end 94 of the
platform assembly 50 tilts downward. The platform assembly 50 comes
to rest in the same plane as the ground on which it has landed,
allowing the front and side barriers to operate in a variety of
ground tilts. Accordingly, the tilt mechanism 70 ensures that there
is no gap remaining between the front end 94 of the platform
assembly 50 and the ground.
[0050] When the wheelchair lift is not in use, it is folded into a
storage configuration and stored inside the vehicle. Because the
platform assembly must fit vertically through the vehicle doorway,
the length of the platform assembly has traditionally been limited
by the height of the vehicle doorway. The height of a typical van
doorway is about 47 inches. If the height of the van doorway is
expanded (modified), it is possible to fit a 52 inch platform
assembly through the doorway. In a preferred embodiment of the
present invention, due the manner in which the wheelchair lift
folds, a longer platform assembly can fit through the vehicle
doorway without requiring an expansion or other modification to the
doorway.
[0051] The folding process of a preferred embodiment of the
wheelchair lift is now described. In reference to FIGS. 5 and 5A,
as the wheelchair lift rises from the ground level configuration to
the entry level configuration, the piston and cylinder assembly 22
is expanding, causing the linkage structure 30 to lift up the
linking arm 40. During the movement of the linkage structure 30,
the fold mechanism cam 100 approaches the cam follower 82 (also
shown in FIG. 3). As the wheelchair lift moves from the entry level
configuration to the storage configuration, the fold mechanism cam
100 contacts the cam follower 82. The fold mechanism cam 100 exerts
force on the cam follower 82, which causes the platform actuator
bar 84 to move in a downward direction. When forced downward, the
platform actuator bar 84 exerts force on the first front platform
56 at connection point 90, causing the first and second front
platforms 56, 58 to rotate about connection point 92.
[0052] In reference to FIGS. 5 and 7, the rear platforms 52, 54 are
pivotally connected to the front platforms 56, 58 along line C.
Because connection point 90 is positioned adjacent line C, when the
platform actuator bar 84 exerts force at connection point 90, the
rear platforms 52, 54 begin to fold toward the front platforms 56,
58 as best shown in FIG. 8. The force exerted at connection point
90 also causes the front platforms 56, 58 to rotate about
connection point 92. As the front platforms 56, 58 rotate about
connection point 92, the front and rear platforms 52, 54 continue
to fold toward each other until the rear platforms 52, 54 are in a
substantially parallel facing relationship with the front platforms
56, 58, as shown in FIG. 9.
[0053] The folding operation of the present invention folds the
platform assembly into quadrants. The first fold is a crosswise
fold, as described above. The second fold is a lengthwise fold,
shown best in FIGS. 10A-10C. When the two-fold process is
completed, the platform assembly is folded into quadrants.
[0054] The second fold of the two-fold process is now described. As
best shown in FIG. 9, the wheelchair lift 10 preferably includes a
fold actuator 110 to facilitate the second fold of the two-fold
process. In a preferred embodiment of the invention, the fold
actuator 110 is preferably an electrical actuator, and more
preferably, an actuator as described in U.S. Provisional Patent
Application No. 60/386,338 filed Jun. 6, 2002 and Ser. No. ______
for Clutch-Driven Limited Force Actuator filed concurrently
herewith, the contents of which are incorporated herein by
reference. However, it is within the scope of the present invention
to utilize a piston and cylinder assembly or other known actuators
as fold actuator 110. The fold actuator 110 is operatively
connected with the power actuating mechanism 20 of the present
invention. After the first fold of the two-fold process is
completed, the fold actuator 110 is activated to exert force on the
second side 104 of the platform assembly 50. By exerting force on
the second side 104, the second side 104 begins pivot with respect
to the first side 102 and to rotate about axis Z.
[0055] The second fold process is best shown in FIGS. 10A-10C,
which show a top plan view of the lift during the folding process.
FIG. 10A depicts a preferred embodiment of the invention after the
first fold is completed but before the second fold has commenced.
FIG. 10B depicts the lift as the fold actuator 110 exerts force on
the second side 104 of the platform assembly 50, causing the second
side 104 to pivot with respect to the first side 102. To assist in
the lengthwise folding of the platform assembly, a torsion spring
(not shown), connects the first and second sides 102, 104 of the
platform assembly. The torsion spring biases the platform assembly
in the folding direction and facilitates the folding once it is
initiated by the fold actuator 110. FIG. 10C depicts the lift at
the completion of the two step folding process, when the second
(lengthwise) fold has been completed.
[0056] In a preferred embodiment of the invention, as best shown in
FIGS. 7 and 10A-C, the second side 104 of the platform assembly 50
is wider than the first side 102. The purpose of offsetting the
pivot line on the platform assembly, and thus making the second
side 104 wider than the first side 102 is to enhance the clearance
of the vehicle doorway when the lift is in a stowed configuration.
When the lengthwise fold is completed, as shown in FIG. 10C, the
second side 104 of the platform assembly 50 is completely cleared
out of the vehicle doorway. As shown in FIGS. 10C and 11, the
second side 104 of the platform assembly 50 preferably extends
behind the first side 102 at an angle, and more preferably, at
about a 45 degree angle. In a stowed configuration, as best shown
in FIG. 12, the width of the wheelchair lift is also minimized as
the second side 104 of the wheelchair lift is cleared out of the
doorway. Accordingly, most of the vehicle doorway is left
clear.
[0057] To allow the various platforms 52, 54, 56, 58 to fold with
respect to each other, the platforms are interconnected by
pivotable connection devices. It is within the scope of the
invention to use any type of connection device that allows the
platforms to pivot with respect to each other. In a preferred
embodiment of the invention, as shown in FIG. 7, hinges are used to
pivotally connect the platforms to each other. A first hinge 120
connects the rear platforms 52, 54 to the front platforms 56, 58
along line C; a second hinge 122 connects the first rear platform
52 to the second rear platform 54 along line A; and a third hinge
200 connects the first front platform 56 to the second front
platform 58.
[0058] To enable the platform assembly 50 to fold crosswise along
line C during the first fold of the two-fold process, the hinges
120 must have a common pivot axis. Accordingly, the hinges 120 are
all preferably positioned along line C such that the pivot axis of
each hinge is along line C. When the pivot axes of the hinges 120
are aligned, the rear platforms 52, 54 fold with respect to front
platforms 56, 58 about line C.
[0059] After the first fold of the two-fold process is completed,
the rear platforms 52, 54 are folded and in a facing relationship
with the front platform 56, 58. Thus, for the second fold of the
two-fold process (the lengthwise fold), the second rear platform 54
and second front platform 58 must fold together. The second rear
platform 54 pivots with respect to the first rear platform 52 about
line A and the second front platform 58 pivots with respect to the
first front platform 56 about line B. To allow the second rear
platform 54 and the second front platform 58 to fold together,
pivot line A must be aligned with pivot line B. If the pivot lines
are not aligned, neither platform will be able to fold in the
lengthwise direction. Accordingly, it is within the scope of the
invention to use any connection device to connect the rear
platforms 52, 54 to each other and the front platforms 56, 58 to
each other, as long as the connection devices pivot about a common
axis during the second fold of the two-step folding process.
[0060] In a preferred embodiment of the present invention, as shown
in FIG. 10B, when the platform assembly is folded in a lengthwise
direction, the second hinge 122 is positioned inside the third
hinge 200. As discussed, to enable the second (lengthwise) fold of
the platform assembly, the pivot axis of the second hinge 122 must
be aligned with the pivot axis of the third hinge 200. However, the
second hinge 122 is not vertically aligned with the third hinge
200. Rather, as shown in FIG. 10B, the second hinge 122 lies inside
the third hinge 200. Accordingly, the types of hinges used must be
selected to ensure that the pivot axis of the second hinge 122
aligns with the pivot axis of the third hinge 200 when the platform
assembly folds in the lengthwise direction.
[0061] In a preferred embodiment of the invention, the second hinge
122 is a piano hinge connected along line A and having a pivot axis
along line A. The third hinge 200 is connected along line B,
however, does not have a pivot axis along line B, because as shown
in FIG. 10B, after the first (crosswise) fold of the two-fold
process is completed, lines A and B are not co-linear. Therefore,
to allow the platform assembly to fold again, this time in the
lengthwise direction, the third hinge 200 must be a type of hinge
that is connected along line B, however, when pivoted, pivots along
an axis that is colinear with line A.
[0062] A preferred embodiment of the third hinge 200 is described
in references to FIGS. 13 through 18. It is envisioned that any
known connection device can be used that would allow the platforms
to fold in the manner described above. As shown in FIG. 13, the
third hinge 200, although physically positioned along line B, has a
pivot axis Z lying outside the hinge. This allows the pivot axis Z
of the third hinge to be aligned with the pivot axis (line A) of
the second hinge 122 to facilitate the lengthwise folding of the
platform assembly.
[0063] As best shown in FIGS. 14 through 18, the third hinge 200
includes a first block hinge 202 and a second block hinge 204. The
first and second block hinges 202, 204 are interconnected by a
plurality of link members 206. For exemplary purposes, four link
members 206 are shown. Each link member 206 has a first end 208
pivotally connected to one of the block hinges 202, 204 and a
second end 210 slidably connected to the other block hinges 202,
204. Furthermore the link members 206 are each pivotally connected
to each other along line B. In a preferred embodiment of the
invention, each link member 206 has a first aperture 212 at its
first end 208, a second aperture 214 at its second end 210, and a
third aperture 216 at a common point 218. To pivotally link the
link members 206 with the block hinges 202, 204, the first
apertures 212 at the first end 208 of the link members 206, are
aligned with corresponding apertures 220 on the block hinges 202,
204. Upon alignment of the apertures 212 and 220, a pin 222 is
inserted through the aligned apertures 212, 220 to pivotally
connect the links 206 with the block hinges 202, 204. To slidably
engage the second ends 210 of the link members 206 with the block
hinges 202, 204, the second apertures 214 are aligned with a slot
224 in the block hinges 202, 204, and a pin 222 is inserted through
the aligned apertures 214 and slot 224. The link members 206 are
preferably arranged in an alternate configuration. In other words,
the first link member 206a is preferably slidably connected to the
first block hinge 202 and pivotally connected to the second block
hinge 204, while the second link member 206b is pivotally connected
to the first block hinge 202 and slidably connected to the second
block hinge 202, and so on. Spring clips 226, spacers 228 and
bushings 230 may be used, as known in the art, to ensure smooth
installation and movement of the link members 206.
[0064] FIGS. 15 and 16 depict the third hinge 200 in a contracted
configuration. In this configuration, the second ends 210 of the
link members 206 are positioned at the outer ends 232 of the slots
224. As the third hinge expands (shown in FIG. 13) the second ends
210 of the link members 206 move toward the inner ends 234 of the
slots. In the fully expanded position, as shown in the FIG. 13, the
second ends 210 of the link members 205 are positioned at the inner
ends 234 of the slots.
[0065] The embodiments described above are exemplary embodiments of
a single arm wheelchair lift. Those skilled in the art may now make
numerous uses of, and departures from, the above-described
embodiments without departing from the inventive concepts disclosed
herein. Accordingly, the present invention is to be defined solely
by the scope of the following claims.
* * * * *