Note: Descriptions are shown in the official language in which they were submitted.
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WHEELCHAIR LIFT
BACKGROUND
Wheelchair lifts, sometimes referred to as vertical lifts or personal
elevators, are typically
purchased by residential or commercial owners and installed to allow staircase-
free elevation
between a lower landing and an upper landing, and can be designed for outdoor
and/or
indoor use. They can be used or adapted for other applications than
wheelchairs, but the use
for wheelchairs (or scooters) is the most common.
Former wheelchair lifts typically include a mobile platform slidingly
connected to a mast
which includes a drive system which controls the vertical movement of the
platform relative
to the mast. To be safe, these former wheelchair lifts include a number of
security features.
For instance, a lower landing gate and an upper landing gate are typically
used to prevent
falls. The lower landing gate is provided on the platform and is locked closed
when the
platform is raised to prevent falling off the platform onto the lower landing.
The upper
landing gate is provided as a separate assembly and is locked closed when the
platform is
lowered to prevent falling off from the upper landing onto the platform. The
locking has
been known to be provided via sensing of the movement of the platform by limit
switches.
The former wheelchair lifts had several drawbacks. For instance the system
which locks
upper landing gate depends on the sensing of the position of the platform. The
sensing of the
position of the platform can be influenced by relative movement between the
elevator
assembly and the upper landing gate assembly. This has been known to cause
inconveniences when the lift is used outdoors, especially in cold climates,
where freezing
and thawing of the ground led to displacements of the elevator assembly
relative to the upper
landing gate assembly. Inconvenient maintenance issues thus occurred.
Further, the mast, which was quite tall and somewhat cumbersome, was placed on
a side of
the platform other than the side of the upper and lower landings, not to
interfere with
mobility through the gates, between the platform and the landings. Room had to
be allocated
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for the mast during planning. Also, significant costs were associated to
design considerations
of the mast to render its appearance less disturbing.
There were other inconveniences as well, including the area which had to be
allocated for the
opening of the upper gate over the upper landing, planning requirements to
ensure that the
upper gate, once opened, would not block access to or from the upper landing,
and the ramp
component which allowed passage between the platform and the lower landing.
Also, the
costs of sensors, and the safety systems globally, in former lifts, were a
concern.
Henceforth, although former wheelchair lifts were satisfactory to a certain
degree, there
remained significant room for improvement.
SUMMARY
Among other innovative features, the instant specification teaches : an upper
landing gate
which can be made part of the mast structure and therefore solve former issues
stemming
from relative movement which occurred between the former lift unit and the
former separate
upper landing gate assembly; a lower landing gate which is hingedly mounted
about a
horizontal axis to the platform and which can serve both as a locked lower
landing gate with
a distal end thereof raised when the platform is raised and a lower landing
ramp to access the
platform from the lower landing once the distal end is lowered; and a locking
system which
uses a slidingly mounted rod with vertical freedom of movement which is
downwardly
biased toward a locking position where the first engaging member associated
with one of the
gates is engaged with a second engaging member which is associated with the
rod, thereby
locking the gate, and a sensor which detects if the rod is in the downward
position, a
combination which allows using a single sensor as both a limit switch or
height sensor to
signal the position to halt the movement of the platform as it reaches the
landing and as a
locking system sensor to trigger a safety alarm and halt the movement of the
platform if the
locking engagement is not detected within a predetermined distance of
movement.
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In accordance with one aspect, there is provided a wheelchair lift comprising
a unitary fixed
structure fixable in position relative to a lower landing and an upper
landing; a mobile
structure slidably connected to the fixed structure and thereby movable in
height between the
lower landing and upper landing, the mobile structure having a platform; and
an elevator
mechanism controlling the sliding movement of the mobile structure relative to
the fixed
structure; the fixed structure further having an upper landing gate integrated
thereto, which
selectively provides or closes access between the upper landing and the
platform.
In accordance with another aspect, there is provided a wheelchair lift
comprising a fixed
structure fixable in position relative to a lower landing and an upper
landing; a mobile
structure slidably connected to the fixed structure and thereby movable in
height between the
lower landing and upper landing, the mobile structure having a platform having
a lower
landing edge adjacent the lower landing when moved to the lower landing
height, and at
least one other edge contiguous to the lower landing edge and having a
receiving structure
upwardly extending therefrom, and a lower landing gate having a proximal end
horizontally
hinged to the lower landing edge of the platform, and being pivotable
thereabout between an
upright closed position where a distal end thereof, opposite the proximal end,
is placed
against the receiving structure, and an open position where the distal end is
pivoted
downwardly against the lower landing and the lower landing gate acts as a ramp
between the
platform and the lower landing, and an actuator mechanism controlling the
pivoting
movement of the lower landing gate to selectively provide or close access
between the lower
landing and the platform; and an elevator mechanism controlling the sliding
movement of
the mobile structure relative to the fixed structure.
In accordance with another aspect, there is provided a wheelchair lift
comprising a fixed
structure fixable in position relative to a lower landing and an upper landing
and having an
upper landing gate; a mobile structure slidably connected to the fixed
structure and thereby
movable in height between the lower landing and upper landing, the mobile
structure having
a platform and a lower landing gate; an elevator mechanism controlling the
sliding
movement of the mobile structure relative to the fixed structure; whereat at
least one of the
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upper landing gate and the lower landing gate has a locking system which is
caused
mechanically engage and lock the corresponding landing gate into a closed
position by
movement of the mobile structure away from the height of the corresponding
landing, while
the elevator mechanism is activated.
In the instant specification, the expression wheelchair lift is used for the
sake of clarity due
to its widespread use in the art, and is not intended to be interpreted
limitatively as restricting
the field of use of the innovations. In the context of this specification, it
is to be understood
that an elevator referred to as a wheelchair lift can be used of other uses
than for
wheelchairs.
DESCRIPTION OF THE FIGURES
In the appended figures,
Figs. 1 to 4 are sequential perspective views showing an example of a
wheelchair lift during
different steps of operation;
Fig. 5 is a block diagram of the wheelchair lift;
Fig. 6 is a flow chart of a locking system of the wheelchair lift;
Figs 7 and 8 are sequential perspective views showing components of a security
system of
the lower landing gate assembly of the wheelchair lift;
Fig. 9 includes Figs. 9A to 9C, which are perspective views showing components
of a
security system of the upper landing gate assembly of the wheelchair lift; and
Fig. 10 is a perspective view showing components of an elevation system of the
wheelchair
lift.
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DETAILED DESCRIPTION
In Fig. 1, an example of a wheelchair lift 10 is shown. The wheelchair lift 10
can be seen to
generally include a mobile structure 12 with a platform 14, which is slidingly
connected to a
fixed structure 16 which has a mast 17. The wheelchair lift 10 is mounted in a
manner to
provide elevation, such as to wheelchair users for instance, between a first-
height area
referred to as the lower landing 18, and a second-, higher-height area
referred to as the upper
landing 20. Typically, the wheelchair lift 10 is intended to allow bypassing a
staircase or
other obstacle (not shown).
To prevent falling down from the upper landing 20 onto the platform 14, an
upper landing
gate 22 is provided. The upper landing gate 22 is provided in an upper portion
24 of the mast
17, to allow passage between two posts 26, 28 of the mast 17 which are
interspaced from
each other by a given width 30. In this example, the width between the posts
26, 28 in the
lower portion 25 is permanently closed. As will be detailed further below, the
upper landing
gate 22 has a locking system which maintains it shut when the platform 14 has
moved
downwardly from the height of the upper landing 20.
The mobile structure also has a lower landing gate 32 which in this embodiment
has a
proximal end 34 which is horizontally hingedly connected to a lower landing
edge 36 of the
platform 14, and an actuator 38 which can pivot a distal end 40 of the lower
landing gate 32
about the hinge 34 between a raised position (Fig. 2) where the lower landing
gate 32 can be
locked as will be detailed further below, and a lowered position (Fig. 1)
where the lower
landing gate 40 can advantageously be used as a ramp 32a between the lower
landing 18 and
the platform 14.
In this example, the lower landing edge 36 of the platform 14 (i.e. the edge
the user runs
across when moving to the lower landing 18) is opposite from the upper landing
edge 42 of
the platform 14, and two other parallel edges 44, 46 have side walls 48, 50
extending
upwardly therefrom and preventing a user to fall to the sides. In this
embodiment, the side
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walls 48, 50 also act as a receiving structure 52 for the lower landing gate
32, as will be
detailed below.
The particular configuration of location of side walls 48, 50 is known in the
art as a
"straight' configuration, or 180 configuration. In alternate embodiments, the
position of the
lower landing gate 32 can be switched with the position of one of the side
walls 48, 50 of the
illustrated embodiments, into a 90 configuration, for instance, in which a
user enters
straight, and exits on one side. In some cases, wheelchair lifts are also
provided with a 0 or
360 configuration. This all depends on the specific area which the lift is to
be adapted to.
The operation of the wheelchair lift 10 can be visualized by sequentially
referring to Figs 1,
2, 3 and 4. In Fig. 1, the lower landing gate 32 is lowered and acts as a ramp
32a allowing
the user to access the platform 14 in the mobile structure 12. Once on the
platform 14, the
user can activate controls 54 (visible only in Fig. 7) and the lower landing
gate 32 is raised
and placed into abutment with the receiving structure 52 provided by the side
walls 48, 50 as
shown in Fig. 2. Subsequently, the mobile structure 12, with the user, can be
raised along the
fixed structure 16, from the lower landing height, shown in Fig. 2, to the
upper landing
height, shown in Fig. 3. When the mobile structure 12 is raised, the lower
landing gate 32 is
locked into position and thereby prevents the user from falling down to the
lower landing 18.
After the mobile structure 12 has been fully raised (as shown), the upper
landing gate 22 is
unlocked, and opened (see Fig. 4), and the user is allowed out from the mobile
structure 12,
onto the upper landing 20. These steps are simply repeated in the opposite
sequence when a
user travels from the upper landing 20 to the lower landing 18.
Referring to Fig. 4, it is seen that the upper landing gate 20, in this
embodiment, is provided
in the form of two door halves 60, 62 which each have a corresponding distal
end 64a, 64b
which come into abutment when the upper landing gate 22 is closed and the two
door halves
60, 62 are aligned (as shown in Fig. 1, for instance). This particular form of
upper landing
gate 62, which can be referred to as a "western style gate", combined by the
positioning of
the upper landing gate 22 in the mast 17 of the fixed structure 16 (which
typically renders it
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at least somewhat recessed from the upper landing 20), results in providing an
upper landing
gate 22 (see Fig. 4) which is highly uncumbersome when open. It will typically
allow one to
circulate on either side of the upper landing 20 and across it when the gate
22 is open. This
can be highly advantageous when compared to traditional single door gates
which were
provided as part of a separate gate assembly and which were thus positioned
closer to the
landing (directly onto the landing). Henceforth, with this design, the
planning requirements
for installation and the versatility of wheelchair lifts can be significantly
improved. Still
referring to Fig. 4, a hinged ramp 66 is provided at the bottom of the upper
landing gate 22
and bridges the gap between the platform 14 and the upper landing 20. Shifting
of the fixed
structure 16 and its mast 17 which can occur when the lift 10 is installed
outdoor in cold
climates due to freezing and thawing of the ground, can be compensated simply
by the use of
the hinged ramp 66 in this configuration.
Referring to the block diagram shown in Fig. 5, the relative movement between
the mobile
structure 12 and the fixed structure 16 is controlled by an elevator mechanism
70, which can
be any suitable elevator mechanism, and which, in turn, can be operated by a
controller 76
which receives input from a user interface.
For security reasons, in this example, both the upper landing gate 22 and the
lower landing
gate 32 have a closed-state sensor 72, 74 which detect whether or not the
corresponding gate
32, 22 is in the closed state. These closed-state sensors 72, 74 can be
connected to the
controller 76, which can be configured to arrest activation of the elevator
mechanism 70 to
prevent movement of the mobile structure 12 (and its platform 14) from the
corresponding
landing height when the gates are not detected to be closed. The controller 76
can also
receive instructions from the user via a user interface 77. In this case, the
controller also
controls operation of the lower landing gate 32 via a gate activator 38
For even greater security, both the upper landing gate 22 and the lower
landing gate 32, in
this example, also have a locking mechanism 78, 80. As will be detailed below,
in both cases
in this example, the locking mechanism 78, 80 is mechanically engaged by
action of the
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relative movement between the mobile structure 12 and the fixed structure 16.
Furthermore,
a locking sensor 82, 84 (also referred to herein as locking system sensor)
detects whether or
not the locking mechanism 78, 80 is correctly engaged. The controller 76 can
be configured
in a manner that if detection of the correct engagement of the locking
mechanism 78, 80 is
not detected within a predetermined travel distance of the mobile structure 12
(which can be
of 2" for example), the mobile structure 12 is prevented from further
movement. This
function is depicted in the flow chart which is provided at Fig 6.
Typically, some form of sensor is used and connected to the controller 76 to
indicate to the
controller 76 that the mobile structure 12 has reached the height of the
corresponding landing
and that the activation of the elevator mechanism 70 is to be stopped. In the
example
described herein and illustrated in the attached figures, the locking system
sensor 82, 84 can
advantageously be used to effect this function, which in turn can reduce costs
and improve
overall simplicity of the design. This is done by configuring the controller
76 to stop the
movement of the mobile structure 12 toward the height of the desired landing
based on the
detection by the corresponding sensor 82, 84 that the corresponding locking
mechanism 78,
80 has been disengaged. This will be described in further detail below. In
alternate
embodiments, a separate height sensor can be used specifically for this
function.
The particulars of the locking system 77 of the lower landing gate 32 are now
detailed with
reference to Figs. 7 and 8. The lower landing gate 32 can be seen to have
hooks 86a, 86b
which are flat and extend perpendicularly from the ramp 32a on opposite sides,
near the
distal end 40, in this embodiment. The receiving structure 52, formed by the
side walls 48,
50 in this embodiment, has corresponding slots 88a, 88b allowing penetration
by the hooks
86a, 86b. Because both sides are identical in this example, only one will be
described in full
detail. A rod 89 is slidingly mounted relative to the receiving structure 52
in a manner to
have vertical freedom of movement. The rod 89 is biased downwardly, by a
compression
spring in this specific example, and has a pin 90 which is functionally
maintained into
locking engagement with the hook 86a by action of the downward bias, in a
position referred
to herein as the locking position (shown in Fig. 8), thereby locking the gate
32 closed. In this
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example, the hook 86a can be said to be a first locking member associated with
the gate 32,
whereas the pin 90 can be said to be a second locking member associated with
the rod 89. In
alternate embodiments, the second locking member can have a male component and
the first
locking member can have a female component, for example. Furthermore, the rod
89 has a
foot 91 (visible in Fig. 7) which extends downwardly and protrudes from the
mobile
structure 12 in a manner that it comes into abutting contact from below with
the ground,
which pushes the rod 89 upwardly when the mobile structure 12 is lowered to
the height of
the lower landing 18, thereby pushing the pin 90 (Fig. 8) out from the hook
86a and
disengaging the mechanical lock of the locking mechanism 78. The locking
system sensor 82
can sense whether or not the rod 89 is at a relative height which corresponds
to its correct
engagement with the hook 86a. A closed-state sensor 72 (or gate close sensor)
detects
whether or not the lower landing gate 32 is in the closed state (shown in Fig.
8) by detecting
the presence of the tip of the hook 86a protruding behind the rod 89. Once the
mobile
structure 12 is raised along a given distance, the foot 91 (Fig. 7) is
eventually freed from the
ground and the pin 90 is thereby brought into engagement with the hook 86a. If
after raising
the mobile structure 12 the predetermined distance, the rod 89 is not detected
to be at the
correct relative position, this indicates that the lock is not correctly
engaged and the
controller can prevent further raising of the mobile structure. If the rod 89
is not correctly
engaged with the hook 86a, the bias will not achieve in pushing the pin 90
into the hook 86a
and the incorrect resulting relative position of the rod will be detected by
the locking system
sensor 82. The fact that both the locking system sensor 82 and the closed-
state sensor 72 are
engaged is the signal to the controller 76 (Fig. 5) that ascension can
commence, in this
embodiment. In this embodiment, the locking system sensor 82 which detects the
relative
position of the rod 89 can also be used as a height sensor to indicate to the
controller that the
mobile structure has reached the height of the lower landing. The rod 89 can
be said to be a
sliding component and the foot 91 can be said to be an abutment portion of the
sliding
component. Alternately, in some embodiments, such a locking system can be used
on only
one side instead of both, such as to reduce costs for instance.
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The particulars of the locking system 92 of the upper landing gate 22 are now
detailed with
reference to Figs. 9A to 9C. Because the locking system 92 of both half-doors
60, 62 (Fig. 1)
are identical in this embodiment, only one is described in detail. The half
door 60 can be
seen to have a hinge connector plate 93 which has three holes 94, 95, 96. The
first one of the
three holes 94 corresponds with a hinge axis 96 of the half-door 60 and is
designed to receive
a hinge pin (not shown). The second one of the three holes 95 is associated
with the closed-
state sensor 74, which determines whether or not the half-door 60 is correctly
closed by
detecting the alignment of the second hole 95 with the fixed-position closed-
state sensor 74.
When the half-door 60 is opened, the second hole 95 is moved out from
alignment, which is
detected. The controller 76 (Fig. 5) does not allow lowering of the mobile
structure/platform
when either one of the half-doors 60, 62 (Fig. 1) is detected to be open.
Finally, the third one
of the three holes 96 is associated with the locking mechanism 80, and is
sized to receive a
locking pin 97 therein which is to lock the closed door 60 in the closed
state. This third hole
96 can be said to be a first locking member associated with the upper landing
gate 22, and
the locking pin 97 can be said to be a second locking member, engageable with
the first
locking member. In this particular example, the locking pin 97 extends
downwardly and is
connected to a rod 98 in a manner that both the rod 98 and the locking pin 97
have
simultaneous and collective vertical freedom of movement. The rod 98 and the
locking pin
97 are downwardly biased by a compression spring in this example. The rod 98
has a foot 99
extending downwardly therefrom. The rod 98 can be said to be a sliding
component and the
foot 99 can be said to be an abutment portion of the sliding component. When
the mobile
structure 12 is raised to the height of the upper landing, it comes into
abutment with the foot
99 and raises the foot 99, thereby moving the rod 89 upwardly which, in turn,
moves the pin
97 upwardly and disengages the mechanical lock. The disengagement of the pin
97 is
detected by a lock system sensor 84. In this particular example, the lock
system sensor 84
can also be used to provide the signal to the controller that the mobile
structure 12 has
reached the upper landing height and that the elevator mechanism can be
stopped. When the
mobile structure 12 is lowered from the upper landing height, the controller
can be
configured to automatically stop the elevator mechanism if the engagement of
the pin 97 into
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the third hole 96 is not detected within a predetermined distance, which can
be of 2" or any
other suitable distance for example.
In both the cases of the locking system 77 of the lower landing gate 32 and
the locking
system 92 of the upper landing gate 22, the locking system sensor can also
serve as a height
sensor, and both cases use a combination of a first locking member associated
with the gate,
and a slidably movable component including a rod which has a second locking
member and
which is downwardly biased into a locking position where the first locking
member is
engaged with the second locking member, and wherein the disengagement of the
locking
members is caused by a downward-facing abutment surface receiving abutting
contact from
below as the mobile structure 12 is moved toward the height of the desired
landing. In both
cases, a sensor which detects the relative movement of the movable component
12 can be
used both as a limit switch or height sensor to halt the movement of the
platform as it arrives
at the desired height, and as a locking system sensor to trigger a form of
safety signal if the
locking engagement is not detected within a predetermined distance as the
mobile structure
12 is moved away from the height of a corresponding landing gate.
It will be understood that in alternate embodiments, the upper landing gate 22
can have a
single door hinged about a horizontal axis like the lower landing gate of the
depicted
embodiment, or hinged about a vertical axis, for instance, and/or the lower
landing gate can
have a vertically hinged door, for example.
Fig. 10 shows the particular elevator mechanism 70 which is used in this
example in further
detail. In this example, the elevator mechanism has two endless screws 102a
102b, one
extending upwardly in each one of the two posts 26, 28 of the mast 17 and to
which the
mobile structure 12 is connected. The endless screws 102a, 102b each have a
driving pulley
104a, 104b at a bottom thereof, which is driven by a single, common, motor 106
via a strap
and pulley arrangement 108. It will be understood that any alternate suitable
elevator
mechanism (sometimes called drive mechanism) can be used to control the
sliding
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movement of the platform 14 relative to the mast 17, such as cable, hydraulic,
or endless
screw mechanisms for instance.
In this embodiment, the actuator 38 which is used to activate the pivotal
movement of the
lower landing gate 32 between the lowered (open) position and the raised
(closed) position
has been selected to be a hydraulic cylinder, for practical considerations.
However, any other
suitable type of actuator, such as a pneumatic actuator or electric motor can
be used if
desired. The particulars of the locking systems can also differ in alternate
embodiments.
The example(s) described above and illustrated is(are) provided for
illustrative purposes. The
scope is indicated by the appended claims.
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