Seat Back Tray Alignment Mechanism for Jam-Free Sliding

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Solution Overview

Problem

Passenger aircraft tray tables often jam when sliding due to unequal force distribution, leading to instability and alignment issues during forward-and-aft movement.

Innovation Solution

A seat back tray assembly with a sliding mechanism incorporating a rail and guide assembly and an alignment mechanism using a pulley system with cables and pulleys to maintain horizontal alignment, ensuring equal force distribution and preventing jamming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a sliding mechanism is added to allow the tray to move forward and aft, then the tray can be positioned closer to or farther from the passenger, but the tray tends to jam when unequal force is applied to one side

Engineering Contradiction:
Improvetray positioning flexibilityVSAvoidsliding mechanism reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an alignment mechanism as an intermediary component between the sliding mechanism and the tray. This alignment mechanism includes alignment features on both the sliding mechanism and the tray that work together to maintain proper alignment during sliding, preventing the tray from jamming when unequal forces are applied. The intermediary alignment features mediate the interaction between the tray and sliding mechanism, ensuring reliable operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The alignment mechanism creates equipotential conditions by ensuring that the tray remains horizontally aligned throughout its sliding range. The alignment features are designed so that the tray maintains a consistent horizontal relationship with the seat back regardless of its position, eliminating alignment variations that could lead to jamming.

Inventive Principle:
Principle #12Equipotentiality

2Ease of operation

If the tray is allowed to slide freely without alignment constraints, then the tray can move easily in forward and aft directions, but the tray loses horizontal alignment during movement

Engineering Contradiction:
Improvetray sliding easeVSAvoidtray horizontal alignment
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The alignment mechanism serves as an intermediary that facilitates smooth sliding while maintaining horizontal alignment. The alignment features are designed to guide the tray's movement, allowing easy sliding in the forward-aft direction while preventing deviation from horizontal alignment. This intermediary system resolves the conflict between ease of operation and alignment stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The alignment mechanism maintains equipotential conditions by ensuring the tray remains in a consistent horizontal state throughout its range of motion. The alignment features create a guided path that preserves the tray's horizontal relationship with the seat back, allowing easy movement without compromising alignment stability.

Inventive Principle:
Principle #12Equipotentiality

3Stability of the object's composition

If alignment features are added to the sliding mechanism, then the tray maintains horizontal alignment during sliding, but the device complexity increases

Engineering Contradiction:
Improvetray horizontal alignmentVSAvoidsliding mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The alignment mechanism is segmented into separate alignment features on the sliding mechanism and corresponding alignment features on the tray. This segmentation allows the alignment function to be distributed across multiple simple components rather than requiring a single complex alignment device. The modular alignment features can be independently manufactured and assembled, reducing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of adding complex active alignment controls to the sliding mechanism, the patent uses passive alignment features that work in reverse - the alignment features on the tray and sliding mechanism are designed to automatically maintain alignment through their geometric relationship, eliminating the need for complex active control systems.

Inventive Principle:
Principle #13The other way round (Inversion)

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 solution allows the tray to slide smoothly and maintain horizontal alignment, preventing jamming and ensuring stable operation even with uneven force application, enhancing passenger convenience and safety.

Implementation Method 1

an alignment mechanism attached to the sliding mechanism for maintaining the tray in a horizontally aligned relationship during the movement

Methodology Applied
Scientific EffectPulley: Pulley

Data Source

PatentEP3749546B1Food tray for passenger seat
Publication Date: 2023.01.25 TIMCO AVIATION SERVICES
  • EP3749546B1 patent drawingFigure 1
  • EP3749546B1 patent drawingFigure 2
  • EP3749546B1 patent drawingFigure 3

AI summary

A seating assembly for a passenger aircraft. The seat system may include at least one passenger seat and a seat back tray assembly mounted onto the back of the passenger seat and movable between a first storage position and a second deployed position. The tray assembly may include (i) a tray having a first and second attachment arm mounted onto the tray for installing the tray onto the back of a seat system; (ii) a sliding mechanism installed on the first and second attachment arms adapted for providing movement between a first forward position and a second aft position to a seated passenger parallel to the first and second attachment arms; and (iii) an alignment mechanism attached to the sliding mechanism for maintaining the tray in a horizontally aligned relationship during the movement. The seat system may further include a PED holder adapted to hold a personal electronic device.