Compact Folding Yoke With Flexible Arms for Rotor Blade Storage
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Solution Overview
Problem
Current rotor blade folding systems cannot accommodate reduced storage space requirements, necessitating a tighter grouping of rotor blades that is not feasible with existing technologies.
Innovation Solution
A folding yoke system with a center yoke, flexible yoke arm, and outboard bearing configuration that allows for the folding of rotor blades by altering the angle between attachment planes and rotating the flexible yoke arm about pivot axes, enabling a more compact stowed position without interfering with inboard and outboard bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single pivot point is positioned outboard of the yoke to avoid interfering with bearings, then the optimal distance between inboard and outboard bearings is preserved, but the storage space required for the rotor blade assembly increases
Solution Approach 1:
The patent moves the pivot point from an outboard position (in the radial direction) to an inboard position (toward the mast), utilizing the axial dimension along the mast. This dimensional shift allows the pivot point to be positioned at or inboard of the inboard bearing, fundamentally changing the spatial arrangement and enabling compact folding while preserving bearing distance
Solution Approach 2:
Instead of positioning the pivot point outboard of the bearings to avoid interference, the patent inverts this arrangement by positioning the pivot point at or inboard of the inboard bearing. This inversion resolves the contradiction by eliminating the need for the pivot point to be outboard, thereby reducing storage space while maintaining optimal bearing spacing
2Reliability
If the pivot point is positioned at least the optimal distance out from the inboard connection to preserve bearing distance, then the optimal distance between inboard and outboard bearings is maintained, but the rotor blade assembly cannot achieve tighter grouping for reduced storage space
Solution Approach 1:
The patent repositions the pivot point along the axial dimension of the mast rather than requiring radial distance outboard. This allows the folding mechanism to achieve compact grouping in the radial direction while the pivot point remains positioned at or inboard of the inboard bearing connection, thereby enabling high storage density without compromising bearing distance
Solution Approach 2:
The patent employs a flexible yoke arm that can dynamically adjust its configuration during folding and stowing operations. This dynamic flexibility allows the system to achieve tight grouping when stowed while maintaining the structural integrity and optimal bearing distance when operational, thereby enhancing adaptability to different storage requirements
Data Source
AI summary
A folding yoke comprising a center yoke pivotally connected to separate foldable flexible yoke arms permits rotor blade fold about a single through bolt connection inboard of a set of bearings. In use, the compact folded arrangement of the rotor blades reduces folded aircraft dimensions in response to ever increasing restricted storage space parameters.