Aircraft Landing Gear Bracing Lock Lever Mechanism
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Solution Overview
Problem
Conventional strut locking devices for aircraft landing gear experience high stress and reduced spring lifespan due to uncontrolled spring extension during retraction, which can hinder efficient folding and stabilization.
Innovation Solution
A bracing device with a lever articulated on the strut, featuring a slot with a return and curved part, limits the spring travel by engaging a finger secured to the arm, allowing the spring to exert a fixed force independent of the arm's angular position, reducing stress and extending the spring's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the spring member is directly coupled to the arm without a lever mechanism, then the structure is simpler, but the spring experiences high stress and reduced lifespan due to uncontrolled extension
Solution Approach 1:
A lever mechanism with a slot is introduced as an intermediary between the spring member and the arm. The slot in the lever guides the finger's movement along a curved path, mediating the force transmission and limiting spring extension. This intermediary structure resolves the contradiction by protecting the spring from excessive stress while maintaining reasonable structural complexity.
Solution Approach 2:
The lever with the curved slot provides geometric feedback to the spring's movement. As the arm articulates, the slot's curved geometry automatically adjusts the lever's position, which in turn limits the spring's extension through the engaged finger. This feedback mechanism ensures the spring operates within safe stress limits without requiring complex control systems.
2Adaptability or versatility
If the spring member has unlimited travel, then it can accommodate full range of motion, but the stress on the spring increases and lifespan decreases
Solution Approach 1:
The slot in the lever is designed with a curved geometry that guides the finger's movement. This curvature transforms the linear extension of the spring into a controlled arc-shaped path, allowing the arm to move through its full range of motion while the spring's extension is geometrically limited. The curved slot thus enables adaptability without excessive stress.
3Reliability
If the spring extension is limited by a lever with a curved slot, then spring stress is reduced and lifespan increased, but the device complexity increases
Solution Approach 1:
The lever serves multiple functions: it transmits force from the spring to the arm, guides the finger's movement through the curved slot, and automatically limits spring extension based on the arm's position. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall device complexity while achieving the reliability benefit.
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 effectively limits spring travel, reducing stress and increasing the lifespan of the spring member, thereby enhancing the stability and efficiency of the strut's folding and deployment processes.
Implementation Method 1
a spring member to return the arms of the stabilizing member to the locking position
Implementation Method 2
the lever being movable between: a confirmation position in which the finger is engaged in a light return part, while the stabilization member is in the locking position; a release position in which the finger is engaged in a curved part of the light that extends along an arc of a circle centered on the axis of articulation
Data Source
Figure 1
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AI summary
The device has a spring unit (23) hitched to a lever (20) articulated on a brace, where the lever has a hole in which a finger (22) is engaged. The finger is integrated to a lower arm (10a) articulated on the brace. The lever moves between a confirmation position, in which the finger is engaged in a return part of the hole when a stabilizing unit is in locking position, and a release position in which the finger is engaged in a curved part (21b) of the hole when the unit is not in the locking position, where the part (21b) extends along an arc of circle centered on articulation axle (X).