Aircraft Armrest Adjustment via Inverted Pivot and Telescoping Trusses
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Solution Overview
Problem
Conventional aircraft pilot seat armrests are cumbersome to adjust and lock due to their pivot location near the elbow, requiring sequential adjustments and robust but slow locking mechanisms to secure the armrest in position for optimal side stick controller operation.
Innovation Solution
An adjustable armrest with a hinged attachment to the seat frame near the seat back, allowing vertical and tilting adjustments from the wrist-end, locked using telescoping struts that form triangular and quadrilateral trusses, enabling smooth and precise positioning and locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the armrest pivot is located near the elbow and adjusted vertically first, then the angle is adjusted, the armrest can be positioned to accommodate the occupant's elbow height and hand position, but the adjustment process becomes cumbersome and time-consuming
Solution Approach 1:
The patent inverts the conventional adjustment sequence by allowing the armrest angle to be adjusted first while the pivot position remains fixed, then the pivot position is adjusted vertically. This reversal eliminates the need for iterative adjustments between position and angle, making the adjustment process more straightforward and less cumbersome while achieving the same positioning capability.
Solution Approach 2:
The armrest adjustment mechanism is segmented into two independent functions: vertical pivot position adjustment and angular tilt adjustment. These are decoupled so that each can be adjusted independently without affecting the other, allowing the user to perform adjustments in a simplified sequence rather than requiring coordinated simultaneous adjustments.
2Reliability
If robust locking mechanisms are used to resist in-flight acceleration, landing and crash loads, the armrest can be securely locked in position, but the locking mechanisms become slow and cumbersome to use
Solution Approach 1:
The patent replaces traditional robust but slow mechanical locking mechanisms (such as screw drives or complex ratchets) with a simplified cam-based locking system. The cam mechanism provides sufficient locking force to resist in-flight loads while allowing rapid engagement and disengagement through simple lever or button actuation, thus maintaining reliability while dramatically improving operation speed.
Solution Approach 2:
The locking mechanism is designed to be self-latching, where the act of adjusting the armrest automatically engages the lock without requiring a separate locking action. The cam mechanism springs into the locked position as the armrest reaches its adjusted position, eliminating the need for manual locking operations while maintaining secure locking under load.
3Device complexity
If the armrest is constrained to tilt about a pivot fixed at the pilot's elbow, the structure is simple, but the armrest cannot freely float to allow natural positioning of the pilot's hand
Solution Approach 1:
The patent adds a second degree of freedom to the armrest by introducing both vertical pivot adjustment and angular tilt adjustment. This transforms the armrest from a single-axis constrained movement to a two-dimensional adjustable system, allowing the armrest to reach multiple positions and orientations to accommodate different pilot sizes and preferences, effectively making it 'float' within an adjustable range rather than being fixed to a single pivot point.
Data Source
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AI summary
An aircraft seat has an adjustable armrest in which the armrest platform (42) is supported by a hinged attachment (46) to an armrest support member (38). The hinged attachment between the armrest platform and the arm support member is located at the wrist-end of the arm support member near the aircraft control stick. The armrest platform and the armrest support are locked into position by means of telescoping struts (62,54) that are controlled at the wrist-end of the arm platform member. The telescoping struts can be selectively locked to create triangular and/or quadrilateral trusses that lock the armrest firmly into position and may include springs or other elements to bias the armrest platform up and forward so that the armrest "floats" when the telescoping struts are released.