Armrest Pivot Assembly With Hidden Retention Pin Access

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Solution Overview

Problem

Existing armrest assemblies in vehicles, particularly in aircraft, require frequent maintenance due to wear and tear in pivoting joints, necessitating costly repairs and skilled labor, while maintaining a discreet connection during service is desirable.

Innovation Solution

An armrest assembly with a pivot block and fixed support member featuring interdigitated stop blocks and a concealed retention pin, allowing easy installation, maintenance, and removal, while ensuring a discreet connection and stable pivoting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a pivoting joint with friction is used to maintain armrest position, then stability is improved, but wear and maintenance requirements increase

Engineering Contradiction:
Improvearmrest position stabilityVSAvoidpivoting joint reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent extracts the friction-generating components (pivoting joint) from the armrest assembly by replacing them with a frictionless pin-through-bore connection. The armrest is attached to the seat back via a simple pin passing through a bore, eliminating the complex pivoting joint that caused wear and maintenance issues, while maintaining stability through the rigid pin connection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical friction-based pivoting joint system with a simpler pin-and-bore mechanical connection. This substitution eliminates the need for friction to maintain position, as the pin directly constrains the armrest to rotate smoothly around the bore axis without generating wear, thereby improving reliability while maintaining stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of repair

If the armrest connection is made visible and accessible, then ease of maintenance is improved, but aesthetic appearance deteriorates

Engineering Contradiction:
Improvearmrest maintenance accessibilityVSAvoidarmrest connection appearance
Core Design Contradiction:
Ease of repairVSShape

Solution Approach 1:

The patent applies the nesting principle by concealing the retention pin within a recess or cavity in the seat back structure. The pin is nested inside the seat back, making it invisible from the exterior while remaining accessible for maintenance through a hidden access point or by removing a decorative cover, thus maintaining aesthetic appearance while enabling easy repair.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent introduces an intermediary element such as a decorative cover or access panel that mediates between the visible aesthetic surface and the hidden maintenance components. This intermediary allows the retention pin to be concealed during normal use while providing a means for accessible maintenance when needed, resolving the contradiction between appearance and ease of repair.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4223640B1Armrest assembly with hidden pivot shaft and discreet retention
Publication Date: 2025.07.02 BE AEROSPACE INC
  • EP4223640B1 patent drawingFigure 1
  • EP4223640B1 patent drawingFigure 2
  • EP4223640B1 patent drawingFigure 3

AI summary

The present disclosure provides an armrest assembly (100) easily installed and removed while in service, and while also maintaining a discreet connection. The armrest assembly (100) includes a pivot block (104) holding an armrest and rotatably coupled to a frame member, for instance a fixed seat spreader (102). The pivot block and frame member have mating stop block features that allow the armrest to rotate while being restrained from motion in upper and lower positions. A central shaft (114) common to the pivot block allows for rotation. A retention pin (118) is installed perpendicular to the axis of rotation through the spreader and is received in an annular groove (116) formed in the shaft to retain the pivot block while allowing its rotation.