Note: Descriptions are shown in the official language in which they were submitted.
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RETRACTABLE VEHICLE STEP
BACKGROUND
The invention relates to a step assembly for a motor vehicle. More
particularly, the invention relates to a step assembly including a step
movable
between a retracted position and an extended position.
It is well-known in the art to provide fixed running boards or fixed step
assemblies alongside 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 are, however, 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.
As an alternative to such fixed running boards, retractable running boards or
step assemblies have been developed. These so-called retractable running
boards 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 for supporting the user.
SUMMARY
According to one aspect of the invention, a step assembly for a motor vehicle
includes a mounting bracket adapted to be attached to the motor vehicle. The
step
assembly includes a step, and an arm having a first end pivotal with respect
to the
mounting bracket and an opposing second end pivotal with respect to the step
for
pivotally moving the step between a retracted position and an extended
position. A
latch assembly is operably coupled to the arm for selectively preventing
pivotal
movement of the arm in order to retain the step in the retracted position.
According to another aspect of the invention, a step assembly for a motor
vehicle includes a mounting bracket adapted to be attached to the motor
vehicle. The
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step assembly includes a step, and an arm having a first end pivotal with
respect to the
mounting bracket and a second end pivotally coupled to the step for moving the
step
between a retracted position and an extended position. A drive shaft is
fixedly
secured to the first end of the arm and rotatable relative to the mounting
bracket. A
pinion is operably connected to the drive shaft and rotatable in response to
rotation of
the drive shaft. A rack link includes a plurality of teeth engaging the
pinion. The
rack link moves linearly relative to the pinion as the pinion rotates to
provide
controlled movement of the step between the retracted and extended positions.
According to yet another aspect of the invention, a step assembly for a motor
vehicle includes a mounting bracket adapted to be attached to the motor
vehicle. The
step assembly includes a step, and an arm including a first end pivotal with
respect to
the mounting bracket and an opposing second end pivotally coupled to the step
for
moving the step between a retracted position and an extended position. A rack
link
includes one end coupled to the mounting bracket and an opposing end coupled
to the
step. The rack link is movable in a linear direction as the step moves between
the
retracted position and the extended position.
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:
Figure 1 is a perspective view of a step assembly according to one
embodiment including a step in an extended position;
Figure 2 is a perspective view of the step assembly including the step in a
retracted position;
Figure 3 is a perspective view of a rack link and pinion, drive shaft, and
latch
assembly for the step assembly;
Figure 4 is a perspective view of the drive shaft operably coupled to the
latch
assembly;
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Figure 5 is a perspective view of the step assembly with a mounting bracket
cut away; and
Figure 6 is an isolated view of the rack link and pinion housed within a rack
guide.
DETAILED DESCRIPTION OF THE EMBODIMENT
Referring to Figures 1 and 2, a step assembly, generally shown at 10, is
provided for assisting individuals entering or exiting a motor vehicle. The
step
assembly 10 includes a mounting bracket, generally indicated at 12, adapted to
be
fixedly secured to an underbody of the motor vehicle. The mounting bracket 12
includes an outboard panel member 14 disposed between a pair of spaced apart
sides
16, 18. A cover member 20 is fixedly secured to one side 16 of the mounting
bracket
12.
The mounting bracket 12 mounts a step 22 to the motor vehicle. The
particular size of the step 22 may vary. The step 22 includes an outboard end
24 and
an opposing inboard end 26. The step 22 also includes a link, generally
indicated at
28, extending out from the inboard end 26 thereof. The link 28 includes a pair
of
spaced apart link members 30, 32 defining a link cavity 34 therebetween. The
step 22
and the link 28 may be formed as a single member or as two separate members
fixedly secured to one another.
Referring to Figure 3, the step assembly 10 also includes an arm 36 having
one end 38 pivotally coupled to the link 28 about a pivot pin 40, and an
opposing end
42 fixedly secured to a drive shaft 44. One end of the drive shaft 44 is
coupled to the
mounting bracket 12 and the drive shaft 44 rotates relative to the mounting
bracket
12. The pivotal movement of the arm 36 relative to the mounting bracket 12 and
the
link 28 moves the step 22 between a retracted position (as shown in Figure 2)
in
which the step 22 is at least partially tucked below the mounting bracket 12
adjacent
the underbody of the motor vehicle, and an extended position (as shown in
Figure 1)
in which the step 22 is spaced further away from the mounting bracket 12 as
well the
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underbody of the motor vehicle to receive individuals entering or exiting the
motor
vehicle.
Referring to Figures 3 through 5, a drive gear 46 is fixedly secured along one
end of the drive shaft 44. The drive gear 46 is in engagement with an
intermediate
gear 48 such that rotation of the drive shaft 44 causes rotation of the
intermediate gear
48. The intermediate gear 48 is fixedly secured to an intermediate shaft 50. A
rack
drive gear 52 is in meshing engagement with the intermediate gear 48. The rack
drive
gear 52 is fixedly secured to one end of a pinion shaft 54. A pinion 56 is
fixedly
secured to an opposing end of the pinion shaft 54.
Referring to Figures 3, 4, and 6, a rack link 58 includes a first end 60 that
pivots relative to the link 28, and a second end 62 that pivots relative to
the mounting
bracket 12. The first end 60 of the rack link 58 is fixedly secured to a pivot
pin 64
extending between the link members 30, 32 of the link 28. The second end 62 of
the
rack link 58 includes a limit pin 66 extending out therefrom. The limit pin 66
is
received within apertures 68 formed in a rack guide 70 which is fixedly
secured to the
outboard panel 14 of the mounting bracket 12. The rack guide 70 houses the
pinion
56 and guides movement of the rack link 58. The limit pin 66 is rotatable
relative to
the rack guide 70 to allow the second end 62 of the rack link 58 to pivot
relative to the
mounting bracket 12.
The pinion 56, which is fixedly secured to the pinion shaft 54 and spaced
apart
from the rack drive gear 52, engages a plurality of teeth 72 formed along the
rack link
58. The rotation of the pinion shaft 54 causes the pinion 56 to rotate.
Rotational
motion of the pinion 56 causes linear movement of the rack link 58 along the
pinion
56.
Referring back to Figures 4 and 5, the step assembly 10 further includes a
latch assembly, generally shown at 74, disposed within the cover member 20 for
selectively retaining the step 22 in the retracted position. The latch
assembly 74
includes a pawl mount 76 fixedly secured to the mounting bracket 12. A pawl
rivet
78 extends through the pawl mount 76. A latch pawl 80 rotates about the pawl
rivet
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78 relative to the pawl mount 76. A wave washer 82 spaces the latch pawl 80
apart
from the pawl mount 76.
The latch assembly 74 also includes a latch hub 84 fixedly secured to the
intermediate shaft 50 for rotation therewith. The latch hub 84 includes a
latch pin 86
extending out therefrom. A deploy spring 88 is coupled to the latch hub 84.
The
deploy spring 88 biases the latch hub 84 away from the latch paw180.
The latch pawl 80 selectively engages the latch hub 84. When the latch pawl
80 is in engagement with the latch hub 84, the latch assembly 74 retains the
step 22 in
the retracted position. When the latch pawl 80 releases the latch hub 84, the
latch hub
84 rotates with the intermediate shaft 50 under the bias of the deploy spring
88 to
allow the step 22 to move to the extended position.
In operation, starting with the step 22 in the retracted position, as shown in
Figure 2, an individual provides an initial "push" action to the step 22 to
activate the
step assembly 10. The initial push action on the step 22 causes the arm 36 to
pivot
relative to the mounting bracket 12 and link 28. Because the arm 36 is fixedly
secured to the drive shaft 44, the drive shaft 44 rotates at the same time.
Due to the
meshing engagement between the drive gear 44 and intermediate gear 48, the
intermediate shaft 50 also rotates. The latch hub 84, which is fixedly secured
to the
intermediate shaft 50, rotates out of engagement with the latch pawl 80 to
release the
step 22 from the latch assembly 74. An additional "push" action to the step 22
causes
the step 22, assisted by the bias of the deploy spring 88, to move into the
extended
position. At the same time, the rack link 58 moves linearly relative to the
pinion 56.
The rack link 58 and pinion 56 provide controlled rotation of the step 22
relative to
rotation of the arm 36.
To return the step 22 to the retracted position, an initial "push" action is
applied to the step 22 to initiate pivotal movement of the arm 36. The drive
shaft 44
rotates in response and, due to the meshing engagement between the drive gear
44 and
the intermediate gear 48, the intermediate shaft 50 rotates. The latch hub 84
thus
begins to rotate towards the latch paw180 against the bias of the deploy
spring 88. An
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additional "push" action further pivots the arm 36 until the latch pawl 80
engages the
latch hub 84 to retain the step 22 in the retracted position.
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.
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