Multi-Rod Hold Open Rod Damping With Non-Circular Members

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Solution Overview

Problem

Hold open rods in multi-rod configurations experience insufficient vibration damping, leading to failures and increased maintenance due to vibrations and accelerations, particularly when operating near natural frequencies.

Innovation Solution

Incorporating a non-circular dampening member, such as a polygonal or multi-lobed shaped member, that rotates within the hold open rod system to effectively dampen vibrations by changing the axis of vibration and introducing intentional dynamic instability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cylindrical dampening member with limited clearance is used, then the hold open rod can accommodate vibration and acceleration, but the dampening is insufficient and vibration occurs at natural frequencies

Engineering Contradiction:

Improvehold open rod reliabilityVSAvoidvibration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by replacing the conventional cylindrical (symmetric) dampening member with a non-circular cross-section dampening member. This asymmetric geometry creates variable clearance between the dampening member and the outer rod, which generates nonlinear damping forces that effectively suppress vibrations at natural frequencies while accommodating operational acceleration.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If robust components are used to withstand vibration, then reliability improves, but manufacturing cost increases

Engineering Contradiction:

Improvehold open rod reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the geometric parameters of the dampening member from a conventional cylindrical shape to a non-circular cross-section. This parameter change transforms the damping mechanism, allowing standard components to achieve superior vibration resistance without requiring more robust (and expensive) materials or oversizing components.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If a noncircular dampening member is used, then vibration dampening is significantly improved, but device complexity increases

Engineering Contradiction:

ImprovevibrationVSAvoiddampening member geometry

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the dampening function from the structural function by using a dedicated non-circular dampening member with variable clearance zones. This segmentation allows the dampening mechanism to be optimized independently, achieving superior vibration control through geometric design rather than complex multi-component assemblies.

Inventive Principle:

Principle #1Segmentation

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 non-circular dampening member significantly reduces vibrations, decreases maintenance needs, and allows for the use of less robust and cost-effective components, providing improved reliability and manufacturing efficiency.

Implementation Method 1

introducing intentional dynamic instability

Methodology Applied

Scientific EffectDynamic instability:

Implementation Method 2

configured to dampen movement of at least one of the following: the inner member and the outer member

Methodology Applied

Scientific EffectVibration dampening: Damping

Data Source

PatentUS11898385B2Device and process to dampen vibration in multi-rod configurations

Publication Date: 2024.02.13 MARATHONNORCO AEROSPACE

AI summary

A hold open rod includes an inner member; an outer member configured to have the inner member slide in and out of the outer member; and a noncircular dampening member arranged on the inner member. The noncircular dampening member being configured to dampen movement of at least one of the following: the inner member and the outer member.