Extendable Vehicle Step Linkage Minimizing Vertical Displacement
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Solution Overview
Problem
Existing extendable and retractable step arrangements for vehicles, such as caravans, face issues with level changes during extension and retraction, which can be problematic for vehicles with limited ground clearance, and often require separate lock mechanisms to prevent accidental retraction, which can complicate the design and increase the risk of mechanical contamination.
Innovation Solution
An extendable and retractable step arrangement using a pivotally connected arm arrangement with a first and second arm, where the second arm is longer than the first arm, allowing for smooth transition between positions without significant level changes, and incorporating a lock mechanism that counteracts torque at the second pivot point, eliminating the need for a separate lock mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pivot principle is used to extend and retract the step, then the step can be extended and retracted, but the level of the step member changes significantly during extension or retraction
Solution Approach 1:
The arm arrangement is designed with specific pivot points and arm length ratios that dynamically adjust the step member's position during extension and retraction. The second arm is made longer than the first arm to create a specific motion trajectory that minimizes vertical displacement while maintaining extension capability
Solution Approach 2:
The invention changes the geometric parameters of the arm arrangement, specifically the length ratio between the first and second arms and the positions of pivot points, to optimize the motion path. This parameter optimization ensures that the step member extends and retracts with minimal level change
2Reliability
If a separate lock mechanism is added to prevent accidental retraction, then the risk of accidental retraction is reduced, but the device complexity increases
Solution Approach 1:
The locking function is merged into the arm arrangement itself. The geometric configuration of the arms and pivot points creates a self-locking effect during normal operation, eliminating the need for separate locking components while maintaining reliability
Solution Approach 2:
The arm arrangement automatically prevents accidental retraction through its own structural design. The specific pivot point configuration and arm length ratios create inherent stability that prevents unintended movement without requiring external locking mechanisms
3Reliability
If a separate lock mechanism is added to lock the step, then accidental displacement is prevented, but torque is transferred to the actuator
Solution Approach 1:
The stabilizing function is combined with the arm arrangement's structural design. The specific configuration of pivot points and arm lengths creates inherent stability that prevents accidental displacement without transferring torque to the actuator
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 allows for the step to be extended and retracted without significant level changes, reduces the risk of accidental retraction, and prevents torque transfer to the actuator, enhancing stability and simplifying the design by eliminating the need for additional locking components.
Implementation Method 1
The arm arrangement comprises at least three arms pivotally connecting the step surface with the object
Data Source
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AI summary
The present invention relates to an extendable and retractable step arrangement (1) for providing an extendable and retractable step member (3) for an object (2), such as a vehicle such as a caravan or a camper (2), which comprises a step surface (4) and an arm arrangement (10) connected to the object (2) and adapted to displace the step surface (4) between a retracted and extended position (A, B). The arm arrangement (10) comprises at least a first arm (20) pivotally connecting the step surface (4) with the object (2) at a first pivot point (11), and a second and a third arm (21, 22). The second arm (21) is pivotally connected to the object (2) at one end (21 a) and pivotally connected to the third arm (22) at the other end (21 b). The third arm (22) is pivotally connected to the second arm (21) and pivotally connected to the step member (3).