Note: Descriptions are shown in the official language in which they were submitted.
CA 02438489 2009-09-08
RETRACTABLE VEHICLE STEP
Background of the Invention
Field of the Invention
This invention relates generally to a stepping assist for motor vehicles. In
particular, the invention relates to a retractable vehicle step which is
movable between
a retracted or storage position and an extended position in which it functions
as a step
assist into the vehicle.
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Description of the Related Art
It is commonly known to add a running board or similar fixed stepping assist
to the side of a motor vehicle, especially to a vehicle with a relatively high
ground
clearance. However, these fixed running boards and other stepping assists have
had
several drawbacks. First, a fixed running board is often too high to act as a
practical
stepping assist and is therefore not very effective in reducing the initial
step height for
the vehicle user. In addition, when using a relatively high running board, the
user is
likely to hit his or her head while climbing into the vehicle cab.
Furthermore, a fixed
running board often extends a significant distance from the side of the
vehicle, and
can be a source of dirt or grime that rubs onto the user's pants or other
clothing as the
user steps out of the vehicle onto the ground surface. Such a fixed running
board is
also frequently struck when the owner of an adjacent parked vehicle opens his
door.
Finally, a fixed running board or step reduces the ground clearance of a
vehicle, and
can often be damaged or torn off entirely when the vehicle is used for offroad
driving.
Accordingly, a vehicle step which overcomes the above-stated problems is
desired.
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Summary of the Invention
Accordingly, in a first embodiment, the present invention provides a
retractable vehicle step assembly, comprising: a step member having a stepping
deck
and a bracket extending inboard from said stepping deck; a first generally
planar
linkage; a second generally planar linkage; said first linkage and said second
linkage
connectable with respect to an underside of a vehicle so as to be pivotable
about a first
axis and a second axis, respectively; said first linkage and said second
linkage
connected to said step member so that said first linkage and said second
linkage are
pivotable with respect to said bracket about a third axis and a fourth axis,
respectively,
said fourth axis located inboard from said third axis; said first linkage and
said second
linkage allowing said step member to move between a retracted position and a
deployed position downward and outboard from said retracted
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position; said stepping deck further comprising an upper surface which defines
a
plane for supporting at least the forefoot of a user, the angle of said plane
with respect
to the horizontal varying as said step member moves between said retracted
position
and said deployed position; said first axis being spaced from said third axis
by a first
distance, said second axis being spaced from said fourth axis by a second
distance,
said first distance and said second distance being unequal; said stepping deck
being
substantially wider than any of (i) a width of said first linkage at said
first axis; (ii) a
width of said second linkage at said second axis; (iii) a width of said first
linkage at
said third axis; and (iv) a width of said second linkage at said fourth axis.
The present invention also provides a retractable step for use with a vehicle,
said retractable step comprising: a first arm connectable with respect to an
underside
of said vehicle so as to be rotatable about a first axis generally orthogonal
to a
direction of access to said vehicle via said retractable step; a second arm
connectable
with respect to said underside of said vehicle so as to be rotatable about a
second axis
generally parallel to said first axis; a
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step member comprising a stepping surface and a support bracket including
first and
second portions extending generally from said stepping surface toward said
arms; said
step member connected to said first arm and rotatable with respect to said
first arm
about a third axis, said step member connected to said second arm and
rotatable with
respect to said second arm about a fourth axis, an end portion of said second
arm
engaging said first and second portions; said step member being moveable
between a
retracted position and a deployed position downward and outward from said
retracted
position; wherein said fourth axis being located inward of and above said
third axis,
and above said stepping surface, and at least a portion of said support
bracket
extending above said stepping surface when said step member is in said
deployed
position.
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The present invention also provides a retractable vehicle step, comprising: a
step member having a stepping deck and a support bracket portion extending
inboard
from said stepping deck; a first support arm; and a second support arm; said
first
support arm and said second support arm connectable with respect to an
underside of
a vehicle so as to be pivotable about a first pivot axis and a second pivot
axis,
respectively; said first support arm and said second support arm connected to
said step
member so that said first support arm and said second support arm are
pivotable with
respect to said step member about a third pivot axis and a fourth pivot axis,
respectively, said fourth pivot axis located inboard from said third pivot
axis; said first
support arm and said second support arm allowing said step member to move
between
a retracted position and a deployed position downward and outboard from said
retracted position; at least one of said first support arm and said second
support arm
extending downward and outboard from said first
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and second pivot axes, respectively, when said step member is in said deployed
position; wherein said stepping deck is substantially wider than said support
bracket
portion; wherein said support bracket portion provides a recessed area into
which said
first support arm is inserted at said third pivot axis.
In a further embodiment, there is provided a retractable vehicle step assist,
comprising: a step member having a stepping deck and a support bracket portion
extending inboard from said stepping deck; and a first unitary support arm
defining an
inboard surface and an outboard surface, a maximum distance between said
inboard
surface and said outboard surface defining a first thickness, said first
support arm
defining a substantially vertical first side and a substantially vertical
second side, a
maximum distance between said first side and said second side defining a first
width,
said first width being substantially greater than said first thickness; a
second unitary
support arm defining an inboard surface and an outboard surface, a maximum
distance between said inboard surface and said outboard surface defining a
second
thickness, said second support arm defining a substantially vertical first
side and a
substantially vertical second side, a maximum distance between said first side
and
said second side defining a second width, said second width being
substantially
greater than said second thickness; said first support arm and said second
support arm
connectable with respect to an underside of a vehicle
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so as to be pivotable about a first axis and a second axis, respectively; said
first
support arm and said second support arm connected to said step member so that
said
first support arm and said second support arm are pivotable with respect to
said step
member about a third axis and a fourth axis, respectively, said fourth axis
located
inboard from said third pivot axis; said first support arm and said second
support arm
allowing said step member to move between a retracted position and a deployed
position downward and outboard from said retracted position; said stepping
deck
further comprising an upper surface which defines a plane for supporting at
least the
forefoot of a user, the angle of said plane with respect to the horizontal
varying as said
step member moves between said retracted position and said deployed position;
said
first axis being spaced from said third pivot axis by a first distance, said
second pivot
axis being spaced from said fourth pivot axis by a second distance, said first
distance
and said second distance being unequal; wherein said support bracket portion
provides a recessed area into which said first support arm is inserted at said
third pivot
axis.
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The present invention also provides a retractable vehicle step assist,
comprising: a step member having a stepping deck and a support bracket portion
extending inboard from said stepping deck; and a first unitary support arm
defining an
inboard surface and an outboard surface, a maximum distance between said
inboard
surface and said outboard surface defining a first thickness, said first
support arm
defining a substantially vertical first side and a substantially vertical
second side, a
maximum distance between said first side and said second side defining a first
width,
said first width being substantially greater than said first thickness; a
second unitary
support arm defining an inboard surface and an outboard surface a maximum
distance
between said inboard surface and said outboard surface defining a second
thickness,
said second support arm defining a substantially vertical first side and a
substantially
vertical second side, a maximum distance between said first side and said
second side
defining a second width, said second width being substantially greater than
said
second thickness; said first support arm and said second support arm
connectable with
respect to an underside of a vehicle so as to be pivotable about a first pivot
axis and a
second pivot axis, respectively; said first support arm and said second
support arm
connected to said step member so that
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said first support arm and said second support arm are pivotable with respect
to said
step member about a third pivot axis and a fourth pivot axis, respectively,
said fourth
pivot axis located inboard from said third pivot axis; said first support arm
and said
second support arm allowing said step member to move between a refracted
position
and a deployed position downward and outboard from said retracted position;
said
stepping deck further comprising an upper surface which defines a plane for
supporting at feast the forefoot of a user, the angle of said plane with
respect to the
horizontal varying as said step member moves between said retracted position
and
said deployed position; said first pivot axis being spaced from said third
pivot axis by
a first distance, said second pivot axis being spaced from said fourth pivot
axis by a
second distance, said first distance and said second distance being unequal;
wherein
said support bracket portion provides an opening in an upper surface of said
support
bracket portion into which opening said first support arm is inserted at said
third pivot
axis.
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All of these and other embodiments are intended to be within the scope of the
invention herein disclosed. This and other embodiments of the present
invention will
become readily apparent to those skilled in the art from the following
detailed
description of the preferred embodiments having reference to the attached
figures, the
invention not being limited to any particular preferred embodiment or
embodiments
disclosed.
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Brief Description of the Drawings
Having thus summarized the general nature of the invention and its essential
features and advantages, certain preferred embodiments and modifications
thereof
will become apparent to those skilled in the art from the detailed description
herein
having reference to the figures that follow, of which:
Figure 1 is a side elevation view of a retractable vehicle step in accordance
with one preferred embodiment of the invention;
Figure 2 is a front elevation view of the retractable vehicle step of Figure
1;
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Figure 3 is a side elevation view of a retractable vehicle step in accordance
with
another preferred embodiment of the invention, in the deployed position;
Figure 4 is an exploded perspective view of the retractable vehicle step of
Figure 3;
Figure 5 is a side elevation view of the retractable vehicle step of Figure 3,
in the
retracted position;
Figures 6A-6B are perspective views of the retractable vehicle step as used in
connection with a vehicle;
Figure 7 is a side view of a further embodiment of a retractable vehicle step,
in the
extended or deployed position;
Figure 8 is a side view of the embodiment of Figure 7, in the retracted
position;
Figure 9 is a perspective view of the embodiment of Figure 7;
Figure 10 is a perspective view of a clutch assembly for use in connection
with the
retractable vehicle step;
Figure 11 is an exploded perspective view of the clutch assembly of Figure 10;
Figure 12 is a perspective view of a further embodiment of the retractable
vehicle
step, in the deployed position; and
Figure 13 is a perspective view of the embodiment of Figure 12, in the
retracted
position.
Detailed Description of the Preferred Embodiment
As a preliminary matter, it should be noted that the terms "forward," "front"
and
"outboard" are used interchangeably herein, as are the terms "rearward,"
"rear" and
"inboard," when describing components of the step structures disclosed herein.
These
terms are to be understood with reference to a direction of ingress into a
vehicle,
"forward"/"front"/"outboard" meaning generally toward the exterior of the
vehicle, and
"rearward"/"rear"/"inboard" meaning generally toward the interior of the
vehicle.
Figures 1 and 2 depict the lower portion of a vehicle 10 having an underbody
12, an
exterior 14, a vertical underbody portion 16 and an under panel 18. A
retractable vehicle
step 20 is shown associated with the vehicle 10. Referring specifically to
Figure 2, the
retractable vehicle step 20 has a stepping member 22, which consists of a
stepping deck 24
with an outboard end 24a, an inboard end 24b, integrally formed support
brackets 26a, 26b,
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and drive brackets 28a, 28b located inward of the support brackets 26a, 26b.
The support
brackets 26a, 26b are pivotally connected to support arms 30a, 30b via clevis
pins 32a, 32b,
at an end of the support brackets 26a, 26b opposite the stepping deck 24.
Similarly, the
support arms 30a, 30b are pivotally connected to anchor brackets 34a, 34b via
clevis pins
36a, 36b, at an end of each support arm opposite the support brackets 26a,
26b. The anchor
brackets 34a, 34b are rigidly connected to the underbody 12 by welding,
bolting, riveting or
other techniques known to those skilled in the art.
The drive brackets 28a, 28b of the stepping member 22 are pivotally connected
to a
drive arm 38 via clevis pins 40a, 40b, at an end of the drive brackets 28a,
28b opposite the
stepping deck 24. As best seen in Figure 2, the drive arm 38 preferably has an
H
configuration and is pivotally connected to anchor brackets 42a, 42b via
clevis pins 44a,
44b at an end of the drive arm 38 opposite the drive brackets 28a, 28b. The
anchor brackets
42a, 42b are rigidly connected to the underbody 12 by welding, bolting,
riveting or other
techniques known to those skilled in the art.
Thus, in the configuration shown in Figure 2, the support arms 30a, 30b are
rotatable about a first axis of rotation A-A which is oriented generally
parallel to a lower
edge 19 of the vertical underbody portion 16, and the drive arm 38 is
rotatable about a
second axis of rotation B-B which is also oriented generally parallel to the
lower edge 19.
The support arms 30a, 30b and brackets 26a, 26b are rotatable with respect to
each other
about a third axis of rotation C-C, and the drive arm 38 and drive brackets
28a, 28b are
rotatable with respect to each other about a fourth axis of rotation D-D. The
third and
fourth axes C-C, D-D are oriented generally parallel to the first and second
axes A-A, B-B.
Figure 1, as a side elevation view of Figure 2, depicts the axes A-A, B-B, C-
C, D-D
as points. The first axis A-A is spaced from the third axis C-C by a first
distance X and the
second axis B-B is spaced from the fourth axis D-D by a second distance Y. (In
other
words, the first axis A-A is spaced from the rotatable connection of the
support arms 30a,
30b to the step member 22 by the first distance X, and the second axis B-B is
spaced from
the rotatable connection of the drive arm 38 to the step member 22 by the
second distance
Y.) In one embodiment, the first and second distances X, Y are unequal; in
another
embodiment the first distance X is greater than the second distance Y. In one
embodiment,
the first axis A-A is located upward from the second axis B-B.
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In one embodiment, as seen in Figure 1, a first aspect ratio may be defined as
the
ratio between (1) the distance between the first and second axes A-A, B-B and
(2) the
length of the arms 30a, 30b as defined by the distance X between the first and
third axes A-
A, C-C. In the embodiment shown in Figure 1, the first aspect ratio is about
0.76.
Likewise, a second aspect ratio may be defined as the ratio between (1) the
distance
between the first and second axes A-A, B-B and (2) the length of the drive arm
38 as
defined by the distance Y between the second and fourth axes B-B, D-D. In the
embodiment shown in Figure 1, the second aspect ratio is about 0.91. A third
aspect ratio
may be defined as the ratio between (1) the distance between the first and
second axes A-A,
B-B and (2) the distance between the third and fourth axes C-C, D-D. In the
embodiment
shown in Figure 1, the third aspect ratio is about 1.32.
With reference now to Figure 1, a motor 46 is rigidly mounted to the underbody
12
on a mounting bracket (not shown) adjacent the retractable vehicle step 20.
The motor 46
turns a pinion gear 48 about an axis roughly parallel to the plane defined by
the underbody
12. The pinion gear 48 meshes with drive teeth 50 formed at the end of the
drive arm 38.
Actuation of the motor 46 causes the pinion gear 48 to rotate and the drive
arm 38 to
counter-rotate with respect to the motor 46 and pinion gear 48, about the
clevis pin 44a. As
the drive arm 38 rotates it pushes the stepping member 22 by virtue of its
connection to the
drive brackets 28a, 28b. Thus, when the motor 46 is caused to rotate, the
motor 46 moves
the retractable vehicle step 20 between a retracted position A wherein the
stepping deck is
desirably generally positioned inward from the exterior of the vehicle or
fixed running
board and an extended position B in which the stepping deck is extended
sufficiently to
provide a step for at least the forefoot portion of a user's foot. As the
retractable vehicle
step 20 moves between the retracted position A and the extended position B
under the
power of the motor 46, the support arms 30a, 30b rotate with respect to the
clevis pins 36a,
36b and 32a, 32b and support and guide the motion of the retractable vehicle
step 20. The
extended position B is reached when the support arms 30a, 30b contact a stop
52 which is
preferably mounted on the vertical underbody portion 16. In one embodiment
(best seen in
Figure 1), the stepping deck 24 is tilted upward when in the retracted
position A, with the
outboard end 24a located upward from the inboard end 24b.
When the retractable vehicle step 20 is in the extended position B, a downward
force exerted on the stepping deck 24 causes the support arms 30a, 30b to bear
against the
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stop 52. This arrangement causes the load on the stepping deck 24 to be borne
primarily by
the support brackets 26a, 26b, support arms 30a, 30b and the stop 52. In the
extended
position B, the retractable vehicle step 20 takes on a geometry such that the
support
brackets 26a, 26b, and support arms 30a, 30b are loaded in tension. The clevis
pins 32a,
32b define a pivot axis of the stepping member 22. The torque generated by a
load on the
stepping deck 24 is opposed by the drive arm 38, which is thus loaded in axial
compression
between the clevis pins 40a, 40b and 44a, 44b. Because the clevis pins 44a,
44b are fixed
in the anchor brackets 42a, 42b, the motor 46 is isolated from the load on the
stepping deck
24.
This aspect of the retractable vehicle step 20 prevents damage to the motor by
eliminating "back-loading," as there is no torque reaction about the end of
the drive arm 38,
even when very heavy loads are placed on the stepping deck 24. Thus the motor
46 is not
needed to exert a counter-torque on the drive arm 38 to support the load on
the stepping
deck 24. This feature also eliminates the need for balky, unreliable clutches
or any other
means of disconnecting the motor 46 from the retractable vehicle step 20, or
retractable
stops or the like to engage and support the vehicle step 20 when in the
extended position.
The retractable vehicle step 20 functions in this manner when in the extended
position B so long as the drive arm 38 is rotated further away from the
vertical in a
counterclockwise direction (as shown in Figure 1) than are the support arms
30a, 30b. That
is, when the drive arm 38 is parallel to, or displaced clockwise beyond
parallel to, the
support arms 30a, 30b, the drive arm 38 will not maintain the support arms
30a, 30b against
the stop 52. Rather, the retractable vehicle step 20 will tend to move toward
the retracted
position A, and the drive arm 38 will tend to rotate counterclockwise (in
Figure 1) about the
clevis pins 44a, 44b. In this situation the motor 46 would be needed to exert
a counter-
torque on the drive arm 38, to maintain the retractable vehicle step 20 in the
extended
position B. As mentioned above, it is undesirable to require the motor 46 to
function in this
manner.
Advantageously, some or all of the arms 30a, 30b, 38 are connected to the step
member 22 within a connection region 31 which is located rearward and upward
from the
stepping deck 24. This configuration minimizes the length and the downward and
forward
travel of the arms 30a, 30b, 38 while facilitating a long overall "reach" for
the step 20, with
convenient placement of the stepping deck 24 when the step is in the extended
position.
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Furthermore, this arrangement permits the use, where desired, of an angled
step member 22
(see Figure 1) which can be retracted against the underbody 12 with minimal
loss of ground
clearance.
In one embodiment, when the step 20 is viewed from the side (see Figure 1) the
third and fourth axes comprise points in the connection region 31, and a line
extending
through the points forms an included angle a of about 10 degrees with respect
to the upper
surface of the stepping deck 24. In another embodiment, the angle a may be
between about
5 and 20 degrees. In still other embodiments, the fourth axis may be located
anywhere
within the connection region 31 rearward and upward of the third axis and the
angle a may
thus be any angle greater than 0 degrees and less than 90 degrees.
A dust cover or cap 54 may be mounted to the lower body panel 18 to provide a
storage location for the stepping member 22 and prevent dust or grime from
collecting on
the stepping deck 24.
With these features the retractable vehicle step 20 provides a practical
stepping
assist for a vehicle user, which can be quickly moved into an extended
position for use and
retracted out of the way when necessary. As detailed above, this functionality
is provided
with a minimum of mechanical complexity and a high level of reliability.
Moreover, the
retractable vehicle step 20 is easily connected to a vehicle's existing
systems to allow even
greater usability. For example, the motor 46 may be connected to the vehicle's
electrical
system to cause the vehicle step 20 to quickly move to the extended position
upon shutting
off the vehicle's engine, placing the vehicle in park, opening a door, or
signaling the power
door-lock system with a remote device or control such as a key fob control.
Similarly, the
motor 46 may be signaled to retract the vehicle step upon starting the engine,
placing the
vehicle in drive, closing or locking the door(s) with which the step is
associated, etc.
Another embodiment of a retractable vehicle step 120 is shown in Figures 3-5.
The
retractable step 120 comprises a stepping member 122 that includes a support
section or
stepping deck 124 bolted or otherwise rigidly connected to an extension
section or a
support bracket 126. The stepping deck 124 has an outboard end 124a and an
inboard end
124b. The stepping deck defines an upper stepping surface. Front and rear
support arms
130a, 130b are rotatably connected to the support bracket 126 via pins 132a,
132b. A rigid
frame 134, which may be configured as necessary for connection to the vehicle
underbody
12, provides a secure mounting for the support arms 130a, 130b which are
rotatably
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mounted to the frame 134 via pins 136a, 136b. It will be appreciated, however,
that any
suitable structure or technique (other than the frame 134) may be employed to
rotatably
connect the arms 130a, 130b to the vehicle.
Thus, as best seen in Figure 4, the front support arm 130a is rotatable about
a first
axis of rotation A-A which is oriented generally parallel to the lower edge 19
(see Figure 5),
and the rear support arm 130b is rotatable about a second axis of rotation B-B
which is also
oriented generally parallel to the lower edge 19. The front arm 130a and the
support
bracket 126 are rotatable with respect to each other about a third axis of
rotation C-C, and
the rear arm 130b and the bracket 126 are rotatable with respect to each other
about a fourth
axis of rotation D-D. The third and fourth axes C-C, D-D are oriented
generally parallel to
the first and second axes A-A, B-B. Figure 3, as a side elevation view of
Figure 4, depicts
the axes A-A, B-B, C-C, D-D as points. The first axis A-A is spaced from the
third axis C-
C by a first distance X and the second axis B-B is spaced from the fourth axis
D-D by a
second distance Y. (In other words, the first axis A-A is spaced from the
rotatable
connection of the front support arm 130a to the step member 122 by the first
distance X,
and the second axis B-B is spaced from the rotatable connection of the rear
support arm
130b to the step member 22 by the second distance Y.) In one embodiment, the
first and
second distances X, Y are unequal; in another embodiment the first distance X
is greater
than the second distance Y. In one embodiment, the first axis A-A is located
upward from
the second axis B-B.
In one embodiment, as seen in Figure 3, a first aspect ratio may be defined as
the
ratio between (1) the distance between the first and second axes A-A, B-B and
(2) the
length of the front arm 130a as defined by the distance X between the first
and third axes A-
A, C-C. In the embodiment shown in Figure 3, the first aspect ratio is about
0.75.
Likewise, a second aspect ratio may be defined as the ratio between (1) the
distance
between the first and second axes A-A, B-B and (2) the length of the rear arm
130b as
defined by the distance Y between the second and fourth axes B-B, D-D. In the
embodiment shown in Figure 3, the second aspect ratio is about 0.93. A third
aspect ratio
may be defined as the ratio between (1) the distance between the first and
second axes A-A,
B-B and (2) the distance between the third and fourth axes C-C, D-D. In the
embodiment
shown in Figure 3, the third aspect ratio is about 1.35.
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With reference to Figure 4, each of the support arms 130 comprises a generally
planar, unitary member which forms two coaxial bearing members 131 at either
end
thereof. The coaxial bearing members may comprise coaxial bores which engage
pins in
the frame and step member to rotatably connect the support arm to each. In
other
embodiments the coaxial bearing members may comprise coaxial axle portions
which
engage bores formed in the frame/step member to provide the rotatable
connections.
Alternatively, one or both of the support arms may form a single bearing
member at one or
both ends, comprising a single full-width bore or a single, central partial-
width bore.
The spacing of the coaxial bearing members 131 defines a connection width CW
at
each end of each support arm. The connection width represents the distance
between the
opposite ends of the engagement of the bearing members with the frame/stepping
member.
For example, in Figure 4 the support arm 130a is rotatably connected to the
frame along an
upper connection width, which equals the distance between the outer edges of
the coaxial
bearing members 131. The support arm 130a is connected to the step member
along a
lower connection width. The support arm 130b likewise defines an upper
connection width
and a lower connection width. These four connection widths are shown in Figure
4 as
being approximately equal, but they may be varied in relative size as desired.
The support arms 130a, 130b also include a rigid crosspiece 133
interconnecting the
bearing members 131. The crosspiece is advantageously of sufficient strength
to prevent
the support arms 130a, 130b from substantially deflecting from their planar
configuration
when a user steps on the stepping deck 124. The crosspiece may take on any
suitable
configuration, such as the full-size member shown, or a series of individual
cross members
extending horizontally or diagonally in an "X" pattern, etc. The high rigidity
of the
crosspiece and the arms 130a, 130b as a whole advantageously permits the width
of the
arms to be minimized while nonetheless providing stable support for the
stepping deck 124
when in the extended position.
The front and rear support arms may take on other forms and configurations,
but
desirably each comprises a generally planar linkage connecting the step member
to the
frame. A "generally planar linkage" may advantageously comprise a generally
planar,
unitary member such as support arm 130a or support arm 130b as shown in Figure
4. An
alternative "generally planar linkage" comprises two or more separate arms
(employed in
place of a single unitary arm) interconnecting the frame and step member, the
arms being
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coplanar by virtue of a common upper axis of rotation associated with
rotatable connection
of the arms to the frame, and a common lower axis of rotation associated with
rotatable
connection of the arms to the step member opposite the frame. As with a
unitary arm, a
multiple-arm planar linkage defines at either end thereof a connection width
extending
between the outer edges of the coaxial bearing members formed by the outermost
arms
making up the linkage.
With further reference to Figures 3 and 4, the support bracket 126 may
comprise any
suitable structural member having sufficient rigidity to resist bending about
its horizontal
and longitudinal axes. Thus the box configuration shown in Figure 4 is
particularly
suitable, but those skilled in the art will appreciate that the bracket 126
can take on other
shapes known to those skilled in the art. The relatively small connection
width of the arms
130 permits the bracket 126 to be made of minimal width as well. By making the
bracket
126 of sufficient length, the stepping deck 124 will be positioned properly
for easy use
when the step 120 is in the deployed position (see Figure 3) and the length of
the arms 130
can be kept to a minimum.
Referring now to Figure 4, the depicted support bracket 126 comprises a
unitary
member forming an upper surface 127, lower surface 129 and first and second
side
segments 141, 143. In the illustrated embodiment, the upper surface 127 forms
an opening
145 through which the lower portions of the first and second support arms
130a, 130b may
be inserted, into a recessed area 149 bounded by the lower surface 129 and the
first and
second side segments 141, 143. In other words, the first and second support
arms 130a,
130b are inserted into the opening 145 or recessed area 149 at the third and
fourth axes C-
C, D-D, respectively.
As best seen in Figure 3, the support bracket 126 preferably forms an angle
with the
stepping deck 124, and thus extends upward and rearward from the substantially
level
(when in the extended position) upper surface of the deck 124. Consequently,
the preferred
angled configuration further enables the length of the support arms 130 to be
minimized.
The step member 122 may thus be said to move between an upward-rotated
orientation in
the retracted position (Figure 5) to a downward-rotated orientation in the
deployed position
(Figure 3). In other words, the step member 122 rotates downward about its
connection
with the support arm 130b when moving to the deployed position, and rotates
upward about
the same connection when moving to the retracted position. When in the
retracted position
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CA 02438489 2003-08-14
the stepping deck 124 tilts upward (with the outboard end 124a located upward
from the
inboard end 124b), minimizing the total downward protrusion of the retractable
step from
the vehicle underbody. Desirably, this upward tilt is at least 100 and,
preferably at least 20 ,
to facilitate any water or debris draining off the step and thereby enhance
its safety when in
use.
With the stepping member 122 moveably connected to the frame 134 via the
support arms 130a, 130b, it can be moved between the retracted position A and
the
extended position B, as shown in Figures 5 and 3, respectively. As with the
embodiment
described previously, the retractable step 120 provides a sturdy step for a
vehicle user when
in the extended position B. The geometry of the stepping member 122, support
arms 130,
and frame 134 causes the arm 130a to be loaded in tension and the arm 130b to
be loaded in
compression when a load is applied to the stepping deck 124 in a manner
similar to that
shown in Figure 1. Accordingly, the arm 130b urges the arm 130a against a stop
152 when
a user steps on the stepping deck 124, by applying a horizontal reaction force
to the step
member 122. The stop 152 prevents motion of the drive arm 138 beyond a
location chosen
so that when the drive arm 138 strikes the stop 152, the step 120 is in a
configuration where
it tends to move further away from the retracted position upon application of
a load to the
stepping deck 124, but is prevented from doing so by virtue of the stop. Due
to this
convergence of factors, the extended step 120 firmly maintains its deployed
position in
which the support bracket 126, and therefore the step member 122, are for
practical
purposes entirely supported by the support arms 130a and 130b, without input
from motor
146 (discussed in further detail below), when stepped upon by a user. This
feature
eliminates the need for a separate locking mechanism, often seen in the form
of a hydraulic
lock, to maintain the stepping deck in the deployed position when in use.
Consequently,
this feature enhances the ease of use of the retractable step, as the user is
not required to
operate or disengage the lock when retracting or deploying the step, thereby
eliminating an
undesirable aspect of prior-art retractable step systems.
A drive system 137 provides powered movement of the step 120 between the
retracted and the extended position. The drive system 137 comprises a drive
arm 138
coupled to a rotor 139, both of which are rotatably mounted on the pin 136a,
and a motor
146 drivingly connected to the drive arm 138 via the rotor 139. The drive arm
138 is
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CA 02438489 2003-08-14
connected to the rotor 139 so as to rotate in concert therewith about the pin
136a. In
another embodiment, the rotor and drive arm form an integral unit.
The motor 146 can be mounted to the frame 134, to the vehicle underbody, or in
any
other suitable location. The motor 146 drives the rotor, drive arm, stepping
member, etc.
via, for example, a worm gear 147 that meshes with teeth (not shown) formed on
the
circumference of the rotor 139. In another embodiment, the motor may comprise
a linear
actuator that pushes or pulls on the circumference of the rotor 139 in order
to rotate it in
either direction. Of course, any suitable means of coupling the motor to the
rotor/drive arm
may be used. Advantageously, a window motor may be used to drive the
apparatus.
Preferably, the motor will adjust for changes in temperature.
The drive system 137, or any drive system employed with any of the embodiments
of the retractable step disclosed herein, may advantageously include a system
to stop the
motion of the step member, arms, etc. when an obstruction is encountered
within the range
of motion of the step, or within the moving parts of the step. Such a system
reduces the
risk of a pinching injury when a person has inadvertently inserted his or her
hand, arm, etc.
within the mechanism, and also reduces the potential for damaging the step
member or
other parts of the retractable step when it approaches or strikes a hard
object such as a curb.
It is contemplated that a standard anti-pinch/anti-strike system may be used,
as is known in
the art.
Advantageously, one or both of the arms 130a, 130b are connected to the step
member 122 within a connection region 131 (see Figure 3) which is located
rearward and
upward from the stepping deck 124. This configuration minimizes the length and
the
downward and forward travel of the arms 130a, 130b while facilitating a long
overall
"reach" for the step 120, with convenient placement of the stepping deck 124
when the step
is in the extended position. Furthermore, this arrangement permits the use,
where desired,
of an angled step member 122 which can be retracted against the underbody 12
with
minimal loss of ground clearance.
In one embodiment, when the step 120 is viewed from the side (see Figure 3)
the
third and fourth axes comprise points in the connection region 131, and a line
extending
through the points forms an included angle R of about 10 degrees with respect
to the upper
surface of the stepping deck 124. In another embodiment, the angle (3 may be
between 5
and 20 degrees. In still other embodiments, the fourth axis may be located
anywhere within
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CA 02438489 2003-08-14
the connection region 131 rearward and upward of the third axis and the angle
0 may thus
be any angle greater than 0 degrees and less than 90 degrees.
A dust cover or cap 154 may be mounted to the lower body panel 18 to provide a
storage location for the stepping member 122 and prevent dust or grime from
collecting on
the stepping deck 124. The dust cover 154 advantageously has a portion that
protrudes
downward from the lower surface of the vehicle and extends across the gap
formed between
the upper surface of the deck 124 and the adjacent vehicle structure, and may
extend or curl
around the outer edge of the deck 124. Thus the dust cover 154 forms a
protective pocket
around the outer edge and upper surface of the deck 124. It has been found
that the dust
cover 154 reduces the accumulation of water, dust, mud and/or debris on the
deck,
providing a substantial benefit in terms of safety and aesthetics while
reducing the chance
of soiling the user's clothes when he or she steps on or stands near the deck.
The retractable step thus utilizes a relatively compact linkage system to
support the
stepping deck 124 when in the deployed position. The relatively short, compact
support
arms 130 can be made of minimal width, as can the frame 134 and support
bracket 126.
The stepping deck 124 can thus be made substantially wider than the
frame/support
arms/support bracket. In other words the stepping deck 124 is preferably
substantially
wider than any of the connection width(s) defined by the support arms.
Advantageously,
the stepping deck is about 2-8 times as wide as the frame, support arms,
support bracket or
any of the connection width(s) defined by the support arms. Thus the
retractable step
provides a wide stepping deck for the vehicle user while minimizing the width
and space
requirements of the frame, linkage system, etc.
The wide stepping deck 124 and relatively narrow frame/support arms/support
bracket permit a single retractable step to serve as a convenient step assist
for two adjacent
doors of a vehicle, without occupying a large amount of space under the
vehicle with the
frame, support arms and support bracket. Figure 6A shows a vehicle 200 having
on one
side thereof a front door 202 and an adjacent rear door 204. In Figure 6A no
portion of the
retractable vehicle step is visible because it is in the retracted position.
Figure 6B shows
the stepping deck 124 of the retractable step after it has moved to the
extended position
(upon opening the front door 202 or in response to other actions as detailed
above). It is
readily seen that the deck 124 provides a convenient step assist for a person
desiring to
enter the vehicle through either of the doors 202, 204. Where the deck 124
extends in front
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CA 02438489 2003-08-14
of about 1/4 of the width of each door, the deck will be sufficiently wider
than the user's
foot to provide an easy-to-use step. Extending the deck to cover about 1/2 the
width of
each door provides an additional safety factor above a 1/4-width deck. A deck
which
extends across substantially the entire width of both doors is most
advantageous in that it
essentially eliminates the need for the user to look down to the step when
placing a foot
upon it, facilitating easy use by a person carrying a large number of items
with them.
More broadly stated, the novel configuration of the retractable step permits
the
width of the stepping deck to be selected largely independently of the width
of the frame,
arms and/or support bracket. Consequently, a stepping deck that is intended to
serve as a
step for two adjacent doors need not extend the entire width of the doors. It
may instead be
only about 4-5 feet wide (in comparison to a standard fixed running board
which is
typically 6-8 feet in width), providing a convenient step while keeping the
size and weight
of the overall device to a minimum. It has been found that this particular
width provides an
optimal balance between providing ease of use (via a relatively wide deck) and
avoiding an
overly large, bulky device. Likewise, the stepping deck of a retractable step
intended for
use with a single vehicle door may be reduced to an optimal deck width which
is less than
the entire width of the door.
Figures 7-11 depict another embodiment 220 of the retractable vehicle step,
attached to a vehicle underbody 12 having a doorjamb 50 adapted to receive a
vehicle door
(not shown), an under panel 18, and a substantially vertical outer panel or
surface 52. The
retractable step 220 comprises a stepping member 222 that includes a stepping
deck 224
bolted or otherwise rigidly connected to a support bracket 226. Front and rear
support arms
230a, 230b are rotatably connected to the support bracket 226 via pins 232a,
232b. The
rear support arm includes a retraction stop 231a and a deployment stop 231b. A
rigid frame
234, which may be configured as necessary for connection to the vehicle
underbody 12,
provides a secure mounting for the support arms 230a, 230b which are rotatably
mounted to
the frame 234 via pins 236a, 236b. The frame 234 may include a forward
extension 235
which forms a rail 235a for attachment of the frame 234 to the vehicle
underbody 12, via
bolting, riveting, welding or other conventional methods. It will be
appreciated, however,
that a wide variety of structure may be used in place of or in addition to the
extension 235
and rail 235a to facilitate attachment of the frame 234 to different vehicle
makes and
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CA 02438489 2003-08-14
models. Likewise, it will be appreciated that any suitable structure or
technique (other than
the frame 234) may be employed to rotatably connect the arms 230a, 230b to the
vehicle.
The front support arm 230a is rotatable about a first axis of rotation A-A
which is
oriented generally parallel to the lowest edge or extension 300 of the vehicle
underbody 12,
and the rear support arm 230b is rotatable about a second axis of rotation
(not shown)
which is also oriented generally parallel to the lowest edge 300. The front
arm 230a and the
support bracket 226 are rotatable with respect to each other about a third
axis of rotation C-
C, and the rear arm 230b and the bracket 226 are rotatable with respect to
each other about
a fourth axis of rotation D-D. The third and fourth axes C-C, D-D are oriented
generally
parallel to the first and second axes.
In one embodiment, as seen in Figure 7, a first aspect ratio may be defined as
the
ratio between (1) the distance between the first and second axes and (2) the
length of the
front arm 230a as defined by the distance between the first and third axes A-
A, C-C. In the
embodiment shown in Figure 7, the first aspect ratio is about 0.21. Likewise,
a second
aspect ratio may be defined as the ratio between (1) the distance between the
first and
second axes and (2) the length of the rear arm 230b as defined by the distance
between the
second and fourth axes. In the embodiment shown in Figure 7, the second aspect
ratio is
about 0.22. A third aspect ratio may be defined as the ratio between (1) the
distance
between the first and second axes and (2) the distance between the third and
fourth axes C-
C, D-D. In the embodiment shown in Figure 7, the third aspect ratio is about
1.00.
As depicted in Figures 7 and 8, the retractable step 220 is moveable between a
retracted position A and an extended position B. When the step 220 is in the
extended
position B, a downward force exerted on the stepping deck 24 causes the
deployment stop
231b to bear against the front support arm 230a. At this point the step 220 is
in a
configuration where it tends to move further away from the retracted position
B upon
application of a load to the stepping deck 224, but is prevented from doing so
by virtue of
the deployment stop 231b. Due to this convergence of factors, the extended
step 220 firmly
maintains its deployed position without input from the motor 246 (discussed in
further
detail below), when stepped upon by a user. This feature eliminates the need
for a separate
locking mechanism, often seen in the form of a hydraulic lock, to maintain the
stepping
deck in the deployed position when in use. Consequently, this feature enhances
the ease of
use of the retractable step, as the user is not required to operate or
disengage the lock when
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CA 02438489 2003-08-14
retracting or deploying the step, thereby eliminating an undesirable aspect of
prior-art
retractable step systems.
Advantageously, one or both of the arms 230a, 230b are connected to the step
member 222 within a connection region 231 (see Figure 7) which is located
rearward and
upward from the stepping deck 224. This configuration minimizes the length and
the
downward and forward travel of the arms 230a, 230b while facilitating a long
overall
"reach" for the step 220, with convenient placement of the stepping deck 224
when the step
is in the extended position. Furthermore, this arrangement permits the use,
where desired,
of an angled step member 222 which can be retracted against the underbody 12
and/or
folded against the arms 230a, 230b to compactly package the step 220 when
retracted,
which in turn facilitates installation of the step 220 within a small space of
the underbody
12, and minimal loss of ground clearance.
In one embodiment, when the step 220 is viewed from the side (see Figure 7)
the
third and fourth axes comprise points in the connection region 231, and a line
extending
through the points forms an included angle y of about 50 degrees with respect
to the upper
surface of the stepping deck 224. In other embodiments, the angle y may be
between 20
and 80 degrees, or between 40 and 60 degrees. In still other embodiments, the
fourth axis
may be located anywhere within the connection region 231 rearward and upward
of the
third axis and the angle y may thus be any angle greater than 0 degrees and
less than 90
degrees.
In the embodiment shown in Figures 7 and 8, the upper surface of the stepping
deck
224 may define a substantially horizontal plane in both the extended and
retracted
positions.
Figures 7, 8 and 9 show that the front support arm 230a preferably has a bowed
configuration, with a relatively straight midsection between two angled end
portions. This
preferred geometry ensures that the retraction and deployment stops 231 a,
231b will contact
the front support arm 230a at a location which is spaced from its rotatable
connections to
the pins 232a, 236a. It has been found that shear loading of the arm 230a near
these
connection points, such as that which may occur in the deployed position
absent the stop
231b, can lead to failure in some circumstances.
In the embodiment presently under discussion, when the retractable step 220 is
in
the retracted position, it is concealed, preferably completely concealed, from
the view of a
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CA 02438489 2003-08-14
typical standing adult curbside observer of the vehicle. In this position the
stepping
member 222, as well as the frame 234 and the remainder of the retractable step
220, is
disposed behind the lowest extension or lower edge 300 of the vehicle
underbody 12.
Preferably, the forward edge of the stepping deck 224 is spaced at least about
1.5-4.5 inches
rearward of the lower portion of the outer panel 52; more preferably, the
forward edge is
spaced at least about 2.5-3.5 inches rearward of the lower portion of the
panel 52; most
preferably, the forward edge is spaced at least about 3.2 inches rearward of
the lower
portion of the panel 52. Furthermore, the lowest-extending point 222a of the
stepping
member 222 is situated above the lowest extension 300 of the underbody 12, or
protrudes
such an amount below the extension 300 (and/or is disposed sufficiently
rearward of the
extension 300) that it substantially remains, and preferably completely
remains, out of the
field of view of a typical standing adult observer positioned outside of the
vehicle. In one
embodiment, the retracted step 220 is not visible to an adult standing 5 feet
from the
vehicle; in another embodiment, the retracted step 220 is not visible to an
adult standing 10
feet from the vehicle; in another embodiment, the retracted step 220 is not
visible to an
adult standing 20 feet from the vehicle.
This concealment is achieved primarily by providing a wide range of motion of
the
stepping member 222. The front and rear support arms 230a, 230b are made
sufficiently
long, and/or provided with a sufficiently wide range of angular motion, to
move the
stepping member 222 rearward and upward into the concealed, retracted position
A. The
arms 230a, 230b are also made sufficiently long in comparison to the stepping
member 222,
and are mounted to the frame 234 on pivot points spaced sufficiently rearward
of the
extension 300, to move the front edge of the stepping deck 234 behind the
extension 300
during retraction. The connection points of the arms 230a, 230b to the frame
234 and
stepping member 222 are selected to prevent either arm from interfering with
the other's
motion over a wide range of travel. The frame 234 includes adequate clearance
to
accommodate the motion of the stepping member 222 and arms 230a, 230b to and
from the
retracted position A. Thus, when the member 222 is retracted, substantially no
portion of
the step 200 is visible to an ordinary "curbside" observer, and a vehicle with
the step 220
installed and retracted will appear substantially identical to such an
observer, to a "stock"
version of the same vehicle.
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CA 02438489 2003-08-14
Figure 9 depicts a preferred drive system 237 for providing powered movement
of
the step 220 between the retracted and the extended position. The drive system
237
preferably comprises a drive arm 238 which is drivingly coupled to the rear
support arm
230b, and is further coupled to a clutch assembly or torque limiter 239. The
clutch
assembly 239 is in meshing engagement with a primary gear system 240 and a
motor 246.
Alternatively, the motor 246 may drive the clutch assembly 239 directly, and
the primary
gear system 240 may be omitted. A subframe 248 may be provided for mounting
the
primary gear system 240 and/or motor 246 with respect to the frame 234. The
clutch
assembly 239 and drive arm 238 are preferably rotatably mounted to the frame
234 so that a
driving force on the teeth of the clutch assembly 239 causes the assembly 239
and the drive
arm 238 to rotate together and move the step 220 to or from the retracted
position.
Figures 10 and 11 show a preferred configuration of the clutch assembly 239
and
drive arm 238 in greater detail. The clutch assembly 239 includes a broached
or splined
hub 250 which is configured for rotatable attachment to the frame 234. The
drive arm 238
includes a broached opening 252 to provide a positive connection to the hub
250 when
mounted thereon. Adjacent the drive arm 238 is a first clutch member 254
formed from a
high-friction clutch material as is known in the art, an input gear 256 having
conventional
gear teeth for receiving a driving force applied by the primary gear system
240 and/or motor
246, and a second clutch member 258, which is preferably similar to the first
clutch
member 254. A broached washer 260 covers the clutch member 258, and a bevel
spring
262 and nut 264 (threadably engaged with the hub) secure the entire assembly
to the hub
250. Thus, under pressure exerted by the spring and nut, the input gear 256 is
frictionally
coupled to the drive arm 238, hub 250 and washer 260 via the clutch members
254, 258.
In normal operation, the input gear 256 and the drive arm 238 will rotate
together
about their common axis of rotation, acting as if a single component, to drive
the step 220
between the retracted and extended positions under the power of the motor 246.
However,
under appropriate circumstances the clutch members 254, 258 will permit
slippage to occur
between the input gear 256 and the drive arm 238, such that relative angular
motion occurs
between the gear 256 and the arm 238. One circumstance under which this may
occur is
when the motor 246 is cut off from its power supply while the step is at or
near the
extended position, and the vehicle user must manually push the step into the
extended
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CA 02438489 2003-08-14
position. The clutch permits the step to be manually retracted in this manner
without back-
loading the motor 246, protecting the motor from damage.
The clutch assembly 239 is also useful in a situation in which the step 220 is
being
moved under power of the motor, but strikes an obstruction which prevents
further motion
of the step. In this situation, the clutch prevents damage to the motor (and
possible injury
where the step has struck a person's hand, leg, etc.) by allowing it to
continue turning under
the power supplied to it while the step is immobilized, avoiding bum-out of
the motor 246.
This provides a further safety measure which can be used, if desired, in
conjunction with a
standard anti-pinch/anti-strike system as discussed above.
Figures 12 and 13 depict a further embodiment 420 of the retractable vehicle
step, in
which two or more retraction assemblies 450 are connected to, and provide
retraction and
deployment of, a single stepping deck 424. Each of the retraction assemblies
450 may
comprise structure which generally similar to any of the embodiments disclosed
above for
the retractable vehicle step; however, the embodiment shown in Figures 12 and
13 utilizes
the mechanism disclosed above in connection with Figures 3-5. One or both of
the
assemblies 450 may include a motor for moving the step between the deployed
position
(Figure 12) and the retracted position (Figure 13).
The assemblies 450 are preferably coupled to the stepping deck 424 at
locations
spaced inward from the outer edges of the deck 424. This configuration limits
the
maximum moment arm defined between a load placed on the deck 424 and either of
the
connection points to the assemblies 450, and reduces the lateral "footprint"
occupied by the
step 420 when connecting the step to a vehicle.
Although this invention has been disclosed in the context of certain preferred
embodiments and examples, it will be understood by those skilled in the art
that the present
invention extends beyond the specifically disclosed embodiments to other
alternative
embodiments and/or uses of the invention and obvious modifications and
equivalents
thereof. Thus, it is intended that the scope of the present invention herein
disclosed should
not be limited by the particular disclosed embodiments described above, but
should be
determined only by a fair reading of the claims that follow.
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