Internal Hold Open Rod Locking for Groove-Free Load Support
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Solution Overview
Problem
Existing hold open rods in the automotive and aviation industries face issues with locking mechanism deterioration over time and unsightly grooves on the rods, which affect their ability to support large loads and maintain functionality.
Innovation Solution
A hold open rod system with a locking mechanism that includes a locking body moving axially and a locking dog that radially moves due to camming action, operated by a release cable, allowing for long-term functionality and load support without causing grooves, featuring a pull-release system for unlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is positioned to ride along the exterior wall of the inner tube, then the hold open rod can be locked in the extended position, but grooves or indentations are formed on the exterior wall which are unsightly
Solution Approach 1:
The locking mechanism is extracted from the exterior wall position and relocated to the interior of the outer tube. The locking dog now engages with a locking slot on the interior surface of the outer tube rather than riding along the exterior wall, eliminating the grooves and indentations that marred the exterior appearance while maintaining the locking function.
2Shape
If the locking mechanism is relocated to the interior of the outer tube, then unsightly grooves are prevented, but the mechanism must reliably lock and unlock under load
Solution Approach 1:
A spring-loaded locking dog acts as an intermediary mechanism that reliably engages with the locking slot on the interior of the outer tube. The spring provides continuous force to ensure positive engagement, while the camming action provides a reliable locking and unlocking sequence that maintains reliability despite the interior relocation.
Solution Approach 2:
The locking mechanism employs dynamic elements including a spring-loaded locking dog that can move between engaged and disengaged states, and a camming action that converts axial movement of the locking plug into radial movement of the locking dog. This dynamic design ensures reliable locking and unlocking under varying load conditions.
3Reliability
If a spring-loaded locking dog with camming action is used, then reliable locking and unlocking is achieved, but the device complexity increases
Solution Approach 1:
Multiple functions are merged into a single integrated locking mechanism assembly. The locking plug, locking dog, spring, and camming surfaces are combined into one cohesive unit that performs locking, unlocking, and load-bearing functions simultaneously, reducing the need for separate components and simplifying the overall device.
Solution Approach 2:
The spring-loaded locking mechanism is self-actuating through camming action. When the hold open rod is extended or retracted, the camming surfaces automatically drive the locking dog into or out of engagement without requiring external actuation, making the system self-servicing and reducing operational complexity.
4Force
If the locking mechanism is designed to support considerable weight, then the hold open rod can hold open doors or hatches, but the locking mechanism may deteriorate over time
Solution Approach 1:
The spring-loaded locking dog provides beforehand cushioning by maintaining constant contact force with the locking slot. This pre-loaded spring mechanism compensates for wear and dimensional changes over time, ensuring that the locking engagement remains reliable even after extended service life and repeated loading cycles.
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 system ensures reliable long-term operation, supports large loads, and prevents unsightly grooves on the rods by providing a durable and efficient locking mechanism that can be easily released, enhancing the hold open rod's functionality and longevity.
Implementation Method 1
compressing a spring; moving a locking plug along an axis of the hold open rod
Implementation Method 2
camming a locking dog along a slanted surface of the locking plug; moving the locking dog radially inward toward the axis
Implementation Method 3
locking the inner and outer members with respect to each other
Data Source
AI summary
A hold open rod may include: an inner member; an outer member configured to have the inner member slide in and out of the outer member; a locking mechanism including a portion attached to the outer member and a portion attached to the inner member; a locking plug configured to move axially along an axis of the inner, outer members; a locking dog configured to move radially between a locking position and an unlocking position and a release cable operatively connected to the locking plug and configured to move the locking plug to the unlocking position. A method of actuating a lock mechanism on a hold open rod may also be provided.