Note: Descriptions are shown in the official language in which they were submitted.
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RETRACTABLE STEP
BACKGROUND
The invention relates to a step assembly for a motor vehicle. More
particularly, the
invention relates to a step assembly including a three bar link for moving a
step between a
stowed position and a retracted position.
It is well-known in the art to provide fixed running boards or fixed step
assemblies
along one side of a motor vehicle to assist individuals in either entering and
exiting or
accessing a motor vehicle having a high ground clearance. These fixed running
boards have,
however, certain disadvantages. For example, such fixed running boards are
often placed at a
height that is not practical for a large number of users. In addition, these
fixed running
boards are susceptible to dirt and mud accumulation, which can then be easily
transferred to a
user's clothing. Moreover, these fixed running boards reduce the ground
clearance for the
motor vehicle and, as such, can be damaged during off-road motor vehicle
operation.
Retractable running boards or step assemblies are generally movable between a
retracted position, in which a step is tucked underneath an underbody of the
motor vehicle,
and an extended position, in which the step is spaced apart from the underbody
of the motor
vehicle to support the user. Retractable running boards commonly incorporate a
four-bar
link, that is, four distinct members for securing the step to the motor
vehicle. The four-bar
links occupy, however, a relatively large amount of space along the underbody
and such
space along the underbody is at a premium.
SUMMARY
A step assembly includes an upper housing adapted to be fixedly secured to a
motor
vehicle. A step is movable relative to the upper housing between a stowed
position and a
deployed position. A single arm is pivotal with respect to the upper housing
and pivotal with
respect to the step in order to form a three-bar linkage for moving the step
between the
stowed and deployed positions.
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According to another aspect of the invention, a step assembly for a motor
vehicle
includes a pair of spaced apart upper housings adapted to be fixedly secured
to the motor
vehicle. A drive shaft extends between and is rotatable relative to the pair
of spaced apart
upper housings. A platform is movable relative to each upper housing between a
stowed
position and a deployed position. An arm extends between each of the spaced
apart upper
housings and the platform. Each of the arms includes a first end fixedly
secured to the drive
shaft and a second end pivotal with respect to the platform for moving the
platform between
the stowed and deployed positions.
According to yet another aspect of the invention, a step assembly for a motor
vehicle
includes an upper housing adapted to be attached to the motor vehicle. A
rotatable shaft is at
least partially disposed within the upper housing. An arm has a first end
fixedly secured to
the rotatable shaft and a second end. A step is fixedly secured to the second
end of the arm
and movable in response to rotation of the rotatable shaft for movement
between a stowed
position generally underneath the motor vehicle and a deployed position spaced
apart from
the motor vehicle in an outboard direction relative thereto.
According to still another aspect of the invention, a step assembly for a
motor vehicle
includes an upper housing fixedly secured to the motor vehicle. The upper
housing includes
a guide slot. A step is movable relative to the upper housing between a stowed
position and a
deployed position. An arm is pivotal with respect to the upper housing and
pivotal with
respect to the step for moving the step between the stowed and deployed
positions. An
extension member is fixedly secured to the arm. The extension member includes
a guide pin
received within the guide slot and movable therewithin as the step moves
between the stowed
and deployed positions.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be readily appreciated as the same becomes better
understood by
reference to the following detailed description when considered in connection
with the
accompanying drawings wherein:
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Figure 1 is a perspective view of a step assembly according to one embodiment
of the
invention;
Figure 2 is a perspective view of a link of the step assembly;
Figure 3 is a side view of the step assembly including a single arm extending
between
the link and an upper housing;
Figure 4 is an enlarged side view of the step assembly;
Figure 5 is an exploded, perspective view of a latch assembly for the step
assembly
including a cover, a latch hub, a pawl mount, and a pawl;
Figure 6 is a perspective view of the latch hub coupled to the pawl mount;
Figure 7 is a perspective view of a step assembly according to a second
embodiment
of the invention;
Figure 8 is an exploded, fragmentary, perspective view of one end of the step
assembly;
Figure 9 is a exploded, perspective view of an arm, drive shaft, and ratchet
mechanism of the step assembly;
Figure 10 is a side view of the ratchet mechanism and the arm;
Figure 11A is a side view of a chain wrapped around a pivot control sprocket;
Figure 11B is a top view of the chain at a first end of the arm;
Figure 12 is a perspective view of a step assembly according to a third
embodiment of
the invention;
Figure 13 is a perspective view of a shaft, arm, and step of the step
assembly;
Figure 14 is a top view of the shaft, arm, and step of the step assembly;
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Figure 15 is a perspective view including a release button operably coupled to
a
deploy lock pin;
Figure 16 is a side view of a latch hub including a deploy spring;
Figure 17 is a perspective view of the latch hub and a pawl mount;
Figure 18 is a fragmentary, perspective view of the step assembly according to
a
fourth embodiment of the invention including an arm having an extension member
received
within a guide slot;
Figure 19 is a side view of a step assembly including the step in the deployed
and
stowed positions; and
Figure 20 is a side view of a step assembly including an extension member
secured to
a link and received within a guide slot.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring to Figure 1, a step assembly according to one embodiment of the
invention
is generally shown at 10. The step assembly 10 includes a step 12 for
supporting individuals
entering or exiting a motor vehicle. The step 12 includes an outboard end 14,
an opposing
inboard end 16, and a stepping surface 18 extending between the outboard 14
and inboard 16
ends.
Referring to Figures 1 through 3, a link, generally indicated at 20, is
fixedly secured
to the step 12 by at least one fastener 22. As shown in Figure 2, the link 20
includes a main
body portion 24 and a pair of spaced apart leg members 26, 28 extending out
therefrom. The
pair of spaced apart leg members 26, 28 defines an opening 30 therebetween.
Each of the
pair of spaced apart leg members 26, 28 terminates at a locking end 32. A cam
member 34 is
coupled to at least one of the pair of spaced apart leg members 26, 28. The
cam member 34
defines a slot 36.
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Referring to Figures 3 and 4, an arm 38 includes a first end 40 pivotally
secured to the
link 20 about pivot pin 42 and an opposing second end 44 pivotally secured to
an upper
housing 46 about a pivot pin 48. The arm 38 provides for pivotal movement of
the step 12
between a stowed position, in which a substantial portion of the step 12 is
tucked below a
body panel of a motor vehicle, and a deployed position (as shown in Figure 1),
in which the
step 12 is spaced further apart from the body panel and available to receive
individuals
entering or exiting the motor vehicle.
A lower slot 50 is formed at the first end 40 of the arm 38. A tilt lock pin
52 is
disposed within the lower slot 50. The tilt lock pin 52 is selectively
received within the slot
36 of the cam member 34. A tilt lock spring 54 is connected to the tilt lock
pin 52.
An upper slot 56 is formed at the second end 44 of the arm 38. A deploy lock
pin 58
is received within the upper slot 56. A deploy spring 60 is connected to the
deploy lock pin
58. The deploy lock pin 58 is selectively positioned within a notch 62 in the
upper housing
46. One end 64 of a release cable or rod 66 is coupled to the deploy lock pin
58 and an
opposing end 68 of the release cable 66 is coupled to the link 20.
The upper housing 46 is fixedly secured to the body panel of the motor vehicle
to
position the step assembly 10 therealong. A latch assembly, generally
indicated at 70 in
Figure 1, is coupled to the upper housing 46 for retaining the step 12 in the
stowed position.
Referring to Figures 5 and 6, the latch assembly 70 includes a latch cover 72
fixedly secured
to the upper housing 46 via a plurality of fasteners 74. A latch hub,
generally indicated at 76,
is operatively coupled to the arm 38 at the second end 44 thereof. More
specifically, the latch
hub 76 and the arm 38 are each fixedly mounted to the pivot pin 48. Therefore,
pivotal
movement of the arm 38 results in pivotal movement of the latch hub 76. The
latch hub 76
includes a main body 78 and a latch pin 80 extending out therefrom. In
addition, a pair of
spaced apart fork members 82, 84 extends out from the main body 78. A deploy
spring 86 is
secured to the latch hub 76.
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A mounting plate 88 is fixedly secured to the upper housing 46 by fasteners
90. A
pawl 92 rotates relative to the mounting plate 88 about a pawl rivet 94. A
washer 96 spaces
the pawl 92 away from the mounting plate 88.
In operation, a user desiring to move the step 12 out of the stowed position
and into
the deployed position provides an initial foot action to the step 12 to pivot
the arm 38. The
pivotal movement of the arm 38 pivots the latch hub 76 and disengages the fork
members 82,
84 thereof from the pawl 92. The deploy spring 86 biases the step 12 towards
the deployed
position. The arm 38 will continue to rotate until the distal locking ends 32
of the link 20
engage the arm 38, which provides a mechanical stop for the step 12. At the
same time, the
deploy lock pin 58 is received within the notch 62 in the upper housing 46.
The step 12 is
thus retained in the deployed position to assist individuals entering and
exiting the motor
vehicle.
To move the step 12 from the deployed position back to the stowed position, an
individual provides an initial foot action to the step 12 in an upward
direction A, shown in
Figure 3. This initial foot action pulls the distal locking ends 32 of the
link 20 downwards.
As a result, the release cable 66 pulls the deploy lock pin 58 out of the
notch 62 in the upper
housing 46. Additional foot action causes pivotal movement of the arm 38. At
the same
time, the latch hub 76 pivots until the latch pin 80 and spaced apart fork
members 82, 84 are
engaged by the pawl 92 so that the latch assembly 70 retains the step 12 in
the stowed
position. In the stowed position, the tilt lock pin 52 is received within the
slot 36 in the cam
member 34 in order to prevent the step 12 from tilting out of the stowed
position.
Referring to Figures 7 through 11, wherein like primed reference numerals
represent
similar elements as those set forth above, the step assembly 10' according to
a second
embodiment of the invention includes a motor 98 operably connected to a drive
shaft 100 via
a plurality of gears 102. The drive shaft 100 fixedly supports two arms 38'.
Rotation of the
drive shaft 100 causes each arm 38' to pivot about the pivot pins 42, 48 to
move the step 12'
between the stowed and deployed positions. It is appreciated that in the
present embodiment,
the step 12' may be a platform step or running board.
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The step assembly 10' includes a ratchet mechanism, generally shown at 104,
having
a pawl 106 interengaging a cam 108 for locking and unlocking the step 12'. A
pawl pin 110
extends out from the pawl 106. A pawl toggle spring 112 biases the pawl 106.
The cam 108
is mounted on the drive shaft 100. Thus, the drive shaft 100, cam 108, and
arms 38' rotate as
a unit.
The step assembly 10' also includes a cable 114 and sector 116 for controlling
rotation of the step 12' relative to the arms 38'. A pin 118 is fixedly
secured to each end of
the cable 114. A ball stud 120 is selectively retained by the sector 116.
In an alternative embodiment, a chain 122 may be utilized in place of the
cable 114
and sector 116, as shown in Figure 11A, for controlling the rotation of the
step 12' relative to
the arms 32'. The chain 122 wraps around a pivot control sprocket 124. A pivot
control gear
126 is fixedly secured to the pivot pin 42'. The pivot control gear 126 is in
meshing
engagement with a pivot control pinion 128. The pivot control pinion 128 is
fixedly mounted
along a pinion shaft 130.
Referring to Figures 12 through 17, wherein like double-primed reference
numerals
represent similar elements as those set forth above, the step assembly 10"
according to a
third embodiment of the invention includes a rotatable shaft 132 having an
upper end 134 and
an opposing lower end 136. The lower end 136 of the shaft 132 is fixedly
secured to the
second end 44" of the arm 38". As a result, rotation of the shaft 132 in one
direction will
move the step 12" from the stowed position to the deployed position and
rotation of the shaft
132 in an opposite direction will move the step 12" from the deployed position
to the stowed
position.
Referring to Figures 14 and 15, a release button 138, which extends out from
an
interior portion of the step 12", is provided to initiate movement of the step
12" from the
deployed position to the stowed position. The release button 138 is coupled to
one end 140
of an actuator rod 142. An opposing end 144 of the actuator rod 142 is fixedly
secured to a
first segment 146 of a bell crank lever, generally indicated at 148, housed
within the step
12". The bell crank lever 148 pivots about a pivot pin 150.
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One end 152 of an actuator release rod 154 is fixedly secured to a second
segment 156
of the bell crank lever 148. An opposing end 158 of the actuator release rod
154 is coupled to
the deploy lock pin 58" disposed within the upper slot 56" at the second end
44" of the arm
38".
The step assembly 10" also includes the latch assembly 70" as set forth in the
first
embodiment. More specifically, the latch assembly 70" retains the step 12" in
the stowed
position. The deploy spring 86" biases the step 12" into the deployed position
when the
latch assembly 70" releases the step 12" from the stowed position.
In operation, to move the step 12" from the stowed position to the deployed
position,
an individual provides an initial foot action to the step 12" in order to
disengage the latch
hub 76" from the pawl 92", upon which the deploy spring 86" biases the step
12" towards
the deployed position. The rotatable shaft 132 rotates and, with it the arm
38", in order to
rotate the step 12" about a vertical axis. The deploy lock pin 58" travels
through the upper
slot 56" until it is received within the notch 62". At this time, the step 12"
is in the
deployed position.
To move the step 12" from the deployed position to the stowed position, the
release
button 138 is pushed by a foot action, which causes the bell crank lever 148
to pivot about the
pivot pin 150 in the direction of arrow A (see Figure 14). As a result, the
actuator release rod
154 is pulled in the direction of arrow B, also shown in Figure 14, and the
deploy lock pin
58" is pulled out of the notch 62". The step 12" is now free to move into the
stowed
position. Continued foot action causes engagement between the latch hub 70"
and the pawl
84", the step assembly 12", the latch assembly 64" locks the step 12" in the
stowed
position.
Referring to Figures 18 through 20, wherein like triple-primed reference
numerals
represent similar elements as those set forth above, in a fourth embodiment of
the invention
the arm 38" of the step assembly 10" includes an extension member 160. The
extension
member 160 may extend out from a middle portion of the arm 38" between the
first 40"
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and 44" ' ends thereof, as shown in Figures 18 and 19, or directly from the
link 18", as
shown in Figure 20. The extension member 160 includes a guide pin 162 at a
distal end 164.
Referring to Figures 18 and 19, the upper housing 40" ' of the step assembly
10" '
includes a pair of spaced apart plates 166 receiving the arm 38" ' and
extension member 160
therebetween. Each of the spaced apart plates 166 includes an aperture 168 for
receiving the
pivot pin 48" at the second end 44" ' of the arm 38" ' to allow for pivotal
movement of the
arm 38" ' relative to the upper housing 46". Each of the spaced apart plates
166 also
includes a guide slot 170 extending between a deploy end 172 and a stow end
174. The guide
slot 170 preferably has an arcuate shape. The guide pin 162 is received within
the guide slots
170 to couple the extension member 160 to the upper housing 46".
In operation, when the step 12" is in the stowed position A, shown in Figure
18, the
guide pin 162 is located at the stow end 174 of the guide slot 170. An initial
foot action in
the downward direction will cause the arm 38" to pivot about the pivot pin 42"
and the
pivot pin 48". In response to such pivotal movement, the guide pin 162 begins
to move
from the stow end 174 of the guide slot 170 to the deploy end 172 thereof.
When the guide
pin 162 reaches the deploy end 172 of the guide slot 170, the step 12" ' has
reached the
deployed position B, also shown in Figure 18, and there is no further pivotal
movement of the
step 12". The step 12" is now available for to support a user thereon.
In order to move the step 12' " from the deployed position back to the stowed
position, an initial foot action in the upward direction is applied to the
step 12". As a result,
the arm 38' " pivots about the pivot pin 42' " and the pivot pin 48". In
response to such
pivotal movement, the guide pin 162 begins to move from the deploy end 172 of
the guide
slot 170 to the stow end 174 thereof. When the guide pin 162 reaches the stow
end 174 of the
guide slot 170, the step 12" ' has reached the stowed position A. In each of
the stowed and
deployed positions, the guide pin 162 is maintained in place by gravity such
that only a
certain amount of force is required to move the step 12" out of either the
stowed or
deployed positions.
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Referring to Figure 20, the extension member 160 is fixedly secured to an
inboard end 175 of the link 18". The guide pin 162 at the distal end 164 of
the
extension member 160 is received within the guide slot 170. The guide pin 162
moves
between the deploy 172 and stow 172 ends of the guide slot 170 as the arm 38"
moves
the step 12" between the deployed and stowed positions. The step assembly 12"
as
shown in Figure 20 provides good packaging options when in the stowed position
and
may be either manually operated or automated.
In each of the four above-described embodiments of the step assembly 10, 10',
10", 10", a three-bar linkage, i.e., the link 20, the arm 38, and the upper
housing 46, is
utilized to move the step 12 between the stowed and deployed positions. The
three-bar
linkage takes up less space along the body panel of the motor vehicle than a
traditional
four-bar linkage. As a result, the step assembly 10, 10', 10", 10' may be
mounted to
a wide variety of motor vehicles.
The invention has been described in an illustrative manner. It is to be
understood that the terminology, which has been used, is intended to be in the
nature of
words of description rather than of limitation. Many modifications and
variations of
the invention are possible in light of the above teachings. Therefore, within
the scope
of the appended claims, the invention may be practiced other than as
specifically
described
