Serrated Connector Member for Composite Load-Bearing Joints

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Solution Overview

Problem

Connecting components made of composite or lightweight materials is challenging due to the weakening of load-transmitting properties when forming openings, and bonded connections are often undesirable.

Innovation Solution

A connector arrangement using a connector member with spline teeth formations that dig into the material surfaces of the components, allowing press-fitting or screwing together for load transmission, suitable for components of similar or dissimilar materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If openings are formed in composite material shaft for bolting or screwing fittings, then mechanical connection is achieved, but load transmitting properties are weakened

Engineering Contradiction:
Improvemechanical connectionVSAvoidload transmitting properties
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The connector member is divided into multiple functional zones: a first engagement portion with spline teeth for the shaft, a second engagement portion with different tooth configurations for the fitting, and a transition portion. This segmentation allows each zone to optimize its connection strategy without compromising the other, enabling mechanical connection without drilling openings in the composite shaft.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connector member acts as an intermediary component between the composite shaft and the metal fitting. It provides a mechanical interface that engages with the shaft through spline teeth distributed along its length, transferring loads without requiring openings in the composite material, thus preserving the shaft's structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If adhesive bonding is used to connect composite material components, then load transmission is maintained, but assembly complexity and reliability concerns increase

Engineering Contradiction:
Improveload transmissionVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention replaces the chemical bonding mechanism of adhesives with a mechanical engagement system using spline teeth. The connector member features distributed spline teeth that mechanically interlock with the composite shaft through friction and normal forces, providing a purely mechanical connection that avoids adhesive complexity while maintaining load transmission capability.

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

3Strength

If spline teeth formations are made with larger dimensions for stronger engagement, then connection strength increases, but stress concentration and material damage increase

Engineering Contradiction:
Improveconnection strengthVSAvoidstress concentration
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the spline tooth dimensions by controlling the ratio between tooth height and root thickness. The spline teeth are designed with specific dimensional parameters where the height is limited to prevent excessive stress concentration, while the root thickness is sufficient to provide engagement strength. This parameter optimization enables strong mechanical engagement without damaging the composite material.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The connector member features varying spline tooth characteristics along its length. The engagement portion has optimized tooth dimensions for strong connection, while the transition portion has different geometry to distribute stresses. This local variation in tooth quality allows strong engagement at critical interfaces while reducing stress concentration in transition zones.

Inventive Principle:
Principle #3Local quality

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

Provides a simple and effective load-bearing connection between components, maintaining structural integrity while accommodating materials with different properties.

Implementation Method 1

a first abutment face provided with a series of spline teeth formations, the dimensions of the first abutment face being selected relative to the first component such that the spline teeth formations thereof dig into the material thereof

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP3963223B1Arrangement for connecting two components with a serrated connector member
Publication Date: 2026.04.15 POLAR TECH MANAGEMENT GRP LTD
  • EP3963223B1 patent drawingFigure 1~6

AI summary

A connector arrangement is described for interconnecting a first component (12) and a second (5) component (14), the connector arrangement comprising a connector member (16) including a first abutment face (20a) shaped to cooperate with a face of the first component (12), the first abutment face (20a) being provided with a series of spline teeth formations (18a), the dimensions of the first abutment face (20a) being selected relative to the first component (12) such that the spline teeth formations (18a) thereof dig into the material thereof, the connector member (16) further comprising a second abutment face (20b) shaped to cooperate with a face of the second component (14), the second abutment face (20b) also being provided with a series of spline teeth formations (18b), the dimensions of the second abutment face (20b) being selected relative to the second component (14) such that the spline teeth formations (18b) thereof dig into the material of the second component (14).