Friction Bushing With Radial Flanges For Adjustable Torque
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Solution Overview
Problem
Existing friction bushings lack a reliable mechanism to provide consistent and adjustable resistance against rotation, particularly in applications like aircraft passenger seats where precise control of force is necessary for mechanisms like meal trays and seat adjustments.
Innovation Solution
A friction bushing design featuring radially arranged flanges around a shaft that apply controlled resistance through pressure, with optional features like a spring clip or lobed shaft for varying resistance, ensuring consistent or adjustable torque profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a friction bushing uses a simple cylindrical design without flanges, then the device complexity is low, but the resistance against rotation is insufficient and not controllable
Solution Approach 1:
The bushing is segmented into multiple functional flanges (first flange, second flange, third flange) arranged radially around the shaft. Each flange serves a specific function: the first flange provides initial friction contact, the second flange provides additional friction contact at a different radius, and the third flange acts as a stop flange. This segmentation allows the bushing to generate controllable resistance torque through distributed friction contacts rather than relying on a single complex mechanism.
Solution Approach 2:
The invention transitions from a simple cylindrical bushing to a multi-dimensional structure by adding radial flanges at different positions and radii. The flanges are arranged in the radial dimension around the shaft, creating multiple friction contact points at different distances from the center. This dimensional change enables the bushing to generate variable resistance torque by utilizing friction at multiple radial positions simultaneously.
2Ease of operation
If the bushing uses multiple flanges arranged radially to provide resistance, then the resistance control is improved, but the manufacturing complexity increases
Solution Approach 1:
Multiple flanges with different functions (friction flanges and stop flange) are merged into a single integrated bushing component rather than using separate parts. The first flange, second flange, and third flange are all formed as part of the same bushing body, which simplifies assembly and reduces the number of components. This merging approach maintains the resistance control functionality while reducing manufacturing complexity compared to using multiple separate friction elements.
Solution Approach 2:
The resistance characteristics are controlled by changing geometric parameters of the flanges (radius, width, thickness) rather than using adjustable mechanical elements. By varying the radial position and dimensions of each flange, the friction torque can be precisely controlled during manufacturing. This parameter-based control approach simplifies the structure compared to mechanically adjustable systems while maintaining ease of operation for achieving desired resistance levels.
3Adaptability or versatility
If the bushing design includes optional features like spring clips or lobed shafts for variable resistance, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The bushing design incorporates dynamic elements such as spring clips that can engage or disengage from the flanges, and lobed shaft configurations that create variable friction zones. These dynamic features allow the resistance characteristics to be changed without replacing the entire bushing. The spring clip can be positioned at different angles to engage different flanges, and the lobed shaft can be rotated to present different friction profiles, providing adaptability while maintaining a relatively simple base structure.
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 design effectively provides controlled and adjustable resistance to rotation, enhancing the functionality of mechanisms like aircraft seat components by ensuring consistent or variable torque, depending on the configuration, thereby improving user control and durability.
Implementation Method 1
the resistance is created by friction resulting from pressure against a shaft by a plurality of flanges projecting off of the bushing along the axial direction of the shaft
Data Source
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AI summary
A friction bushing for being positioned on a shaft for friction-retarded rotation relative to the shaft, including a housing having a bore for receiving the shaft and a flange plate positioned on the housing around the bore. A plurality of flanges are carried by the flange plate and adapted for extending axially outwardly from the flange plate and along circumferentially-spaced apart areas of the shaft for frictionally-engaging axially-extending areas of the shaft.