Land vehicles – Wheeled – Attachment
Reexamination Certificate
2002-10-31
2004-06-08
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Attachment
C280S163000, C182S088000
Reexamination Certificate
active
06746033
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to steps for overland vehicles, and more specifically to movable steps utilizing a motor to extend and retract the steps during use.
BACKGROUND OF THE INVENTION
Extendable vehicle steps and running boards are commonly used and come in a variety of shapes and sizes. These devices generally include a step or footrest surface that may be moved between a retracted position and an extended operational position to assist passengers entering or exiting the vehicle. For example, U.S. Pat. Nos. 3,762,742 and 4,708,366 both describe a step affixed to an arm having a proximal end rotatably connected to the vehicle. The step rotates about a single axis in going between its retracted and extended positions. U.S. Pat. Nos. 3,887,217; 4,073,502; 4,110,673; and 6,375,207 describe vehicle steps having complicated extension assemblies. Each assembly includes parallel links that rotate a lateral step inward and outward in going between retracted and extended positions.
While prior art devices provide adequate functionality, many of them do not adequately secure the step in the retracted position. This can result in the step inadvertently extending during travel, especially when traveling off-road or on a bumpy surface. Thus, a need exists for a vehicle step that will not easily move from its retracted position unless purposefully commanded to do so. Ideally, the assembly should not be complicated or require components that are difficult to machine, manufacture, or assemble. The present invention is directed to fulfilling these needs and others, as described below.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a step assembly is described for use with a vehicle chassis. The assembly includes a step, one or more support brackets, one or more link assemblies, a motor, and drive shaft. The support bracket is fastened to the vehicle chassis. The step has at least one support arm that is pivotally connected to the support bracket. The axis of rotation of the arm to the bracket is about a longitudinal first axis. The motor and drive shaft are also supported by the support bracket, with the drive shaft capable of axial rotation. The drive shaft rotation is thus parallel to the pivot axis of the support arm and support bracket. The link assembly includes a first link having a proximal end, fixedly attached to the drive shaft in a radial manner, and a distal end. The link assembly further includes a second link with a proximal end rotatably connected to the first link distal end and a distal end rotatably connected to the support arm at a location outward of the first axis.
During use, the step has a raised, or up, position in which the first and second links are located generally adjacent one another in an upright orientation. The step further includes a down, or lowered, position in which the first and second links are located generally in line with one another in an upright orientation. The first link is made to rotate by rotation of the drive shaft about its longitudinal axis. In one embodiment, the distal end of the first link rotates inward and upward when initiating movement of the step from the down position to the up position, and in a reverse manner when moving the step from the up position to the down position.
In accordance with other aspects of this invention, in the down position, the point of rotation between the first and second links is located laterally outward of the drive shaft's axis of rotation. In one embodiment, the support bracket includes a stop that extends outwardly from the bracket. In the up position, the first link abuts the stop.
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Christensen O'Connor Johnson & Kindness PLLC
Phan Hau
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