Double-Flanged Clevis Pins for Flight Control Cable Retention
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Solution Overview
Problem
Conventional aircraft control cable pulley systems face issues with maintaining proper separation and positioning of control cables, which can lead to interference and binding, hindering aircraft flight control.
Innovation Solution
The use of double flanged clevis pins mounted between the pulley mounting bracket and pulley to maintain control cables within the pulley groove, preventing deformation of bracket side walls and potential cable chafing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pulley mounting brackets are used without additional positioning elements, then the structure is simple, but the control cables cannot be reliably maintained within the pulley grooves leading to cable binding and interference
Solution Approach 1:
The bracket structure is segmented into functional zones: the pulley mounting portion and the cable guidance portion with ledges. This segmentation allows the bracket to simultaneously provide structural support and cable positioning functions, ensuring cables remain within grooves without adding separate complex positioning mechanisms.
Solution Approach 2:
The bracket is designed with multi-functionality by incorporating ledges that serve dual purposes: they act as structural elements of the bracket while simultaneously functioning as cable positioning elements that prevent cables from leaving the pulley grooves. This eliminates the need for separate cable retention devices.
2Volume of moving object
If pulleys are mounted close to bracket side walls, then space is efficiently utilized, but the bracket side walls may deform over time causing cable chafing
Solution Approach 1:
Cable retention ledges are introduced as intermediary elements between the pulleys and the bracket side walls. These ledges act as mediators that prevent direct contact and potential deformation transfer from the bracket walls to the cables, while still allowing compact positioning of pulleys within the bracket structure.
Solution Approach 2:
The ledges provide beforehand protection by creating a physical barrier that prevents cables from being exposed to potential bracket wall deformation. This prior cushioning ensures cables are protected from chafing before deformation can occur, maintaining cable integrity in compact configurations.
3Ease of manufacture
If control cables are allowed to move freely, then ease of installation is improved, but cables may interfere with other components and binding may occur
Solution Approach 1:
The bracket ledges perform preliminary positioning action during assembly, guiding cables into the correct position within pulley grooves before the system becomes operational. This preliminary action ensures cables are properly positioned from the start, preventing interference with other components while maintaining installation simplicity.
Solution Approach 2:
The ledges extend in a new dimension (perpendicular to the cable path) to create a containment structure. This dimensional addition provides cable retention without restricting cable movement along its operational path, maintaining installation ease while preventing harmful cable displacement and binding.
Data Source
AI summary
Double flanged clevis pins are provided in aircraft flight control pulley systems and are mounted between the opposed side walls of the pulley mounting bracket at a closely spaced separation distance relative to a respective pulley and the cable retained within the pulley groove. The outboard facing surface of each of the clevis pin flanges is positioned in abutting relationship with an adjacent inboard facing surface portion of a respective one of the opposed side walls of the mounting bracket while outboard ends of the clevis pin extend coaxially outwardly therefrom and through the adjacent mounting bracket side wall. The central pin section of the clevis pin is therefore closely spaced above an adjacent portion of the circumferential edge of the pulley in which an aircraft control cable is received to thereby maintain the control cable within the pulley groove and prevent deformation of the bracket side walls.