Retractable Vehicle Step Drive Using a Coiled Flexible Cable
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Solution Overview
Problem
Existing retractable steps for vehicles are bulky, costly, and complex, leading to interference with mechanical parts, high maintenance costs, and reliability issues in harsh weather conditions.
Innovation Solution
A compact retractable platform with a movement device using a commercial electric gearmotor assembly and coiled flexible cable, integrated with a straight guide and tubular sheath, allowing for efficient and reliable operation without significant equipment investment, utilizing readily available parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional motorized retractable steps are used, then the step can be extracted and retracted, but the assembly dimensions become large, interfering with mechanical parts and structural elements
Solution Approach 1:
The patent replaces complex mechanical transmission mechanisms (crank-connectors, speed reducers) with a direct electric motor system. The motor's rotational output is directly coupled to the step mechanism through a simple transmission, eliminating the need for intermediate mechanical components and significantly reducing assembly dimensions.
Solution Approach 2:
The patent uses a coiled flexible cable instead of rigid mechanical linkages to transmit force and motion. This flexible cable allows for compact packaging within the box-like container while maintaining the necessary mechanical advantage for step extraction and retraction.
2Volume of moving object
If special design solutions are used to reduce dimensions, then the assembly becomes more compact, but construction costs and selling prices increase
Solution Approach 1:
The patent employs standard, commercially available electric motors and mechanical components that can be used across multiple vehicle models and applications. This universal approach eliminates the need for custom-designed special members and containment casings, significantly reducing tooling and manufacturing costs.
Solution Approach 2:
The patent achieves dimension reduction by optimizing the arrangement and orientation of standard components within the available space, rather than by redesigning the components themselves. This allows use of off-the-shelf parts while achieving compact integration.
3Extent of automation
If complex mechanical parts are used, then the step can be motorized, but reliability decreases in harsh weather conditions with water, snow, mud, and ice
Solution Approach 1:
The patent replaces complex mechanical transmission systems with a simplified electric motor-driven system having fewer moving parts. This reduction in mechanical complexity minimizes potential failure points, particularly in harsh environmental conditions where ice, water, and mud can interfere with mechanical linkages.
Solution Approach 2:
The motorized system is designed to be self-contained within the box-like container, with all essential components integrated into a compact assembly that protects them from environmental exposure. The system requires minimal maintenance and can operate reliably in adverse weather conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective, reliable, and compact retractable platform that minimizes interference with vehicle mechanics, streamlines spare parts management, and maintains functionality in adverse weather conditions.
Implementation Method 1
an electric gearmotor assembly, arranged inside said box-like container, intended to rotate, in both directions, a gearwheel
Implementation Method 2
a coiled flexible cable of suitable length engaged in gearing with said gearwheel in a tangential arrangement, so that the rotation of the latter imparts straight forwards or backwards translations thereto
Data Source
Figure 1~2
Figure 3~5
AI summary
A retractable platform (100) comprising a box-like container (110) and an extractable step (120) is provided with a movement device (1) adapted to move the step (120), with the platform (100) provided for equipping access doors (P) of commercial, camping or similar vehicles (V), wherein the movement device (1) comprises: an electric gearmotor assembly (2), derived from an automotive regulator, capable of imprinting straight forwards or backwards translations to a coiled flexible cable (3); a straight guide (4), integral with said box-like container (110), wherein the front portion of said coiled flexible cable (3) is slidable, held straight and parallel to the direction (X) of motion of said extractable step (120); a bracket (5), fixed to the front end of said coiled flexible cable (3), external to said straight guide (4) and made integral with said extractable step (120), so as to be able to push out or retract the latter; a shaped tubular sheath (6), rearwardly associated with said electric gearmotor assembly (2), intended to receive and house the rear portion of said coiled flexible cable (3), as a result of the return stroke of the extractable step (120) in said box-like container (110).