Eccentric Bushing Assembly for Shear Transfer in Removable Panels

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for attaching panels to underlying support structures face challenges in transferring shear forces due to pin misalignment and variations, leading to over-constrained conditions that make panel removal difficult, and are often incompatible with fixed pin structures or sensitive to perpendicularity errors.

Innovation Solution

The use of an eccentric bushing assembly that includes an outer eccentric bushing, an inner eccentric bushing, and a spherical bushing, which allows for axial, radial, and rotational movement to align with connecting pins, facilitating shear force transfer while accommodating misalignments and enabling easy panel removal and reinstallation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If multiple pins are used to attach the panel to the underlying support structure, then the shear force transfer capability is improved, but the attachment becomes over-constrained and difficult to remove due to normal variations from nominal pin positions

Engineering Contradiction:

Improveshear force transfer capabilityVSAvoidpanel removal difficulty

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The bushing is designed with eccentric geometry that allows it to rotate and translate relative to the pin, dynamically adapting to position variations. This movement capability enables the bushing to maintain proper alignment and shear transfer while accommodating manufacturing tolerances, and allows for easy panel removal by reversing the insertion motion

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The eccentric bushing changes its effective geometry parameters through rotation and translation movements. By altering the relative position between the bushing center and pin center, the system adapts to position variations while maintaining functional requirements for both strength and removability

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If oversized clearance holes are used in the panel to receive pins, then the ease of installation is improved, but the shear transfer properties are negated and reliance on friction increases

Engineering Contradiction:

Improveease of installationVSAvoidshear transfer properties

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The eccentric bushing serves as an intermediary component between the pin and the panel opening. It transforms the oversized clearance hole into an effective tight-fit connection by using its eccentric geometry to self-align with the pin, thereby restoring shear transfer properties while maintaining ease of installation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If match drilled pin holes are used between the panel and underlying support structure, then the shear transfer capability is improved, but the panel cannot be removed unless pins are individually removable and additional manufacturing expense is incurred

Engineering Contradiction:

Improveshear transfer capabilityVSAvoidmanufacturing expense and complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention extracts the alignment and adaptation function from the pin itself and places it in the eccentric bushing component. This allows the use of simple drilled holes without expensive match drilling operations, while still achieving proper alignment and shear transfer through the bushing's eccentric geometry

Inventive Principle:

Principle #2Taking out (Extraction)

4Ease of operation

If a single eccentric bushing is provided on each side of a panel to attach to two pins, then alignment of holes with pins is facilitated, but removal is impeded by perpendicularity tolerances and it is not suitable for fixed pin structures

Engineering Contradiction:

Improvealignment facilitationVSAvoidcompatibility with fixed pin structures

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The eccentric bushing design provides universal applicability by accommodating both removable and fixed pin structures. The same eccentric geometry that facilitates alignment also enables adaptation to position variations in fixed pins, making the solution versatile across different application scenarios

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12071974B2Eccentric bushing for redundant pinning of removable panels

Publication Date: 2024.08.27 RAYTHEON CO

AI summary

An eccentric bushing assembly comprises an outer eccentric bushing configured to be disposed in an opening of a panel comprising a central axis. The outer eccentric bushing is operable to float axially, rotate circumferentially, and to move radially with respect to the central axis. The eccentric bushing assembly further comprises an inner eccentric bushing disposed radially inward from the outer eccentric bushing and interfacing with the outer eccentric bushing, the inner eccentric bushing is operable to rotate relative to the outer eccentric bushing. The eccentric bushing assembly further comprises a spherical bushing comprising a through hole operable to receive a connecting pin therein and to rotate in at least one degree of freedom. The rotation of the spherical bushing can facilitate alignment of an axis of the pin with the through hole.