Cam-Actuated Locking Linkage for Tolerance-Robust Unlocking
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Solution Overview
Problem
Conventional locking mechanisms for deployable components, such as ram air turbine actuators, are sensitive to manufacturing accuracy, prone to wear, and require additional components like cross-rods that can be costly and complex, making them less suitable for lightweight and compact aircraft applications.
Innovation Solution
A locking mechanism utilizing a rotational rod with a cam feature that engages with a linkage assembly to prevent overcentering and facilitate axial movement of the lock bolt, replacing the need for a cross-rod and solenoid-based systems, allowing for simpler, less expensive, and more reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional solenoid-based unlocking mechanism with cross-rod and linkage arrangement is used, then the lock bolt can be reliably unlocked, but the device complexity and weight increase
Solution Approach 1:
The patent removes the cross-rod from the conventional linkage arrangement, extracting this problematic component that caused wear, complexity, and manufacturing sensitivity issues. The remaining linkage is simplified to work directly with the lock bolt and solenoid, eliminating the need for the cross-rod while maintaining the unlocking function.
Solution Approach 2:
The linkage is divided into separate links (first link, second link, third link) that are independently mounted and pivoted, allowing each component to be optimized and assembled separately. This segmentation reduces overall complexity and improves manufacturability while maintaining reliability.
2Reliability
If a conventional linkage arrangement with cross-rod is used, then the lock bolt can be unlocked, but the weight and size of components increase
Solution Approach 1:
The cross-rod is completely removed from the system, eliminating its weight and the weight of associated mounting hardware. The simplified linkage arrangement uses fewer and lighter components to achieve the same unlocking function.
Solution Approach 2:
The functions of the cross-rod and the linkage are merged into a simplified direct linkage arrangement where the links connect directly to the lock bolt and mounting structure, eliminating redundant components and reducing overall weight.
3Reliability
If a conventional linkage arrangement is used, then the lock bolt can be unlocked, but manufacturing precision requirements increase due to sensitivity
Solution Approach 1:
The cross-rod is removed, eliminating the complex joints and connections that required high manufacturing precision. The simplified linkage has fewer connection points and less sensitive geometry, reducing tolerance requirements.
Solution Approach 2:
The linkage is designed with pivot points that allow controlled movement and adjustment, making the system more tolerant of manufacturing variations. The dynamic pivoting capability compensates for minor dimensional deviations in assembled components.
4Reliability
If a conventional cross-rod based system is used, then the lock bolt can be unlocked, but the mechanism is prone to wear and damage
Solution Approach 1:
The cross-rod is completely removed, eliminating the source of wear and damage problems. The simplified linkage has fewer moving parts and connection points, reducing opportunities for wear and simplifying maintenance.
Solution Approach 2:
The linkage design allows natural alignment and self-centering of components during operation, reducing stress concentrations and wear on individual parts. The spring-loaded lock bolt provides self-lubrication through controlled movement.
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 mechanism provides a reliable and cost-effective solution by reducing sensitivity to manufacturing tolerances and eliminating the need for complex cross-rod systems, ensuring safe and efficient deployment of deployable components while meeting aviation regulations.
Implementation Method 1
a linkage assembly spring (5) to bias the linkage assembly into a first, locked, position
Implementation Method 2
a rotational rod (1) having a cam (120) formed thereon with a cam surface in engagement with the linkage assembly in the region of the pivot point
Implementation Method 3
a solenoid assembly arranged, in a first mode, to rotate the rotational rod such that the cam acts as a stop against the linkage assembly at the pivot point in a locked position
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A locking mechanism comprising a linkage assembly (6) comprising: a first link (6a) and a second link (6b) joined at a pivot point (110); a linkage assembly spring (5) to bias the linkage assembly (6) into a first, locked, position; a rotational rod (1) having a cam (120) formed thereon with a cam surface in engagement with the linkage assembly in the region of the pivot point (110); a solenoid assembly (3) arranged, in a first mode, to rotate the rotational rod (1) such that the cam (120) acts as a stop against the linkage assembly (6) at the pivot point (110) in a locked position, and, in a second mode to rotate the rotational rod (1) such that the cam surface presses against the linkage assembly sufficiently (6) to overcome the linkage assembly spring (5) and to force the linkage assembly (6) into a second, unlocked position.