Tube Connector Assembly That Avoids Rivet Stress Risers

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Solution Overview

Problem

Existing passenger seat base frame assemblies in aircrafts rely on rivets or through-bolts for connection, which can cause stress risers and require additional apertures, leading to potential stress concentration and galvanic corrosion.

Innovation Solution

A connector with adjustable dimensions, featuring stoppers and an adjustment slot, is used to secure elongated tubes without rivets, allowing for flexible material options like rubber or plastic, reducing stress concentration and enabling quick assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rivets or through-bolts are used for connection, then structural strength is improved, but stress concentration and galvanic corrosion occur

Engineering Contradiction:
Improvestructural strengthVSAvoidstress concentration and galvanic corrosion
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

A rubber or plastic connector is introduced as an intermediary element between the fastener and the tubular structural members. This flexible connector distributes the mechanical loads over a larger area, eliminating stress risers while preventing direct contact between dissimilar metals, thus preventing galvanic corrosion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connector material properties are changed from rigid (metal) to flexible (rubber or plastic). This parameter change allows the connector to deform and distribute stresses uniformly, eliminating stress concentration while maintaining structural integrity under dynamic loads.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additional apertures are created for rivets or through-bolts, then connection reliability is improved, but stress concentration increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidstress concentration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful function of creating apertures in the tubular structural members is eliminated. Instead of passing fasteners through the tubes, the invention extracts the connection function to a separate flexible connector that interfaces with the tubes externally or internally without requiring apertures in the structural members.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If traditional connectors are used, then assembly is secure, but assembly time increases

Engineering Contradiction:
Improveassembly securityVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The connector is designed with flexible material properties that allow it to be inserted and secured quickly without requiring precise alignment or complex fastening procedures. The flexibility enables the connector to adapt to slight variations in positioning, reducing assembly time while maintaining secure connection.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4396082B1Connector for a tube assembly in a passenger seat
Publication Date: 2025.11.05 ZODIAC SEATS US LLC
  • EP4396082B1 patent drawingFigure 1
  • EP4396082B1 patent drawingFigure 2
  • EP4396082B1 patent drawingFigure 3

AI summary

Described are base frame assemblies for a passenger seat having an elongated tube (202, 204) and a connector (206). The elongated tube (202, 204) may include an inner surface, an outer surface, and a connecting aperture extending from the inner surface to the outer surface. The connector (206) may include a first end, a second end, a central opening (311) extending from the first end to the second end, a first stopper (302) at the first end, a second stopper (304) proximate to the second end, a contact surface (306) between the first stopper (302) and the second stopper (304), and an adjustment slot (310) defined as extending from the first end to the second end. The connector (206) may be positioned within the connecting aperture such that a portion of the elongated tube contacts the contact surface (306) between the first stopper (302) and the second stopper (304) that may together overlap a portion of the inner surface and outer surface of the elongated tube.