Flex Eyeglass Hinge With Internal Cable Routing for Over-Rotation

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Solution Overview

Problem

Conventional flex hinges for electronic eyeglasses cause damage to flexible PCB cables due to deformations, traction forces, and sticking, and fail to hide the cable externally while allowing smooth rotation and over-rotation of the temples.

Innovation Solution

A hinge design with an internally hollow central body and elastic means, allowing the flexible PCB cable to slide without sticking or torsion, hidden within the hinge structure, and featuring an inclined plane for smooth rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the external contact edge profile between temple and front is not parallel to the rotation axis of the hinge, then the hinge allows over-rotation to prevent damage, but the cable undergoes deformations and sticking that lead to damage

Engineering Contradiction:
Improveover-rotation capabilityVSAvoidcable integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The hinge is divided into three separate bodies (first body connected to front, second body connected to temple, third body as connector) that can move independently relative to each other. This segmentation allows the cable to pass through separate channels in each body, preventing sticking and deformation during over-rotation while maintaining the non-parallel external profile for over-rotation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A third body is introduced as an intermediary component between the first body (front) and second body (temple). This intermediary body provides an additional degree of freedom and a separate cable passage channel, acting as a mediator that decouples the rotational motion from cable stress, allowing over-rotation without cable damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Shape

If the cable is hidden within the hinge structure, then aesthetic appearance is improved, but the cable may stick and wear out during rotation

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidcable durability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The hinge is segmented into three bodies with separate internal channels for cable passage. This segmentation allows the cable to be hidden within the hinge structure for aesthetic purposes while each segment provides a dedicated, smooth pathway that prevents sticking and wear during rotation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hinge bodies are designed with internally hollow structures that form flexible channels for cable passage. These hollow bodies allow the cable to move freely within protected pathways, maintaining both aesthetic appearance (hidden cable) and reliability (no sticking or wear).

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If the hinge allows smooth rotation and over-rotation, then ease of operation is improved, but the cable is subjected to traction forces and deformations

Engineering Contradiction:
Improverotation smoothnessVSAvoidcable stress
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The hinge is segmented into three independently movable bodies, each with its own cable passage channel. This segmentation allows smooth rotation and over-rotation of the temple relative to the front while the cable passes through separate, protected pathways in each body, eliminating traction forces and deformations on the cable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cable passage is routed through the third dimension (internal hollow spaces of the three bodies) rather than along the plane of rotation. This dimensional change allows the cable to remain stationary relative to each hinge segment while the segments move, enabling smooth rotation without cable stress.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4081853B1Hinge of the flex type for eyeglasses
Publication Date: 2026.02.18 LUXOTTICA SRL
  • EP4081853B1 patent drawingFigure 1
  • EP4081853B1 patent drawingFigure 2
  • EP4081853B1 patent drawingFigure 3

AI summary

A hinge of the flex type (1) for eyeglasses, the peculiarity of which consists in that it comprises an internally hollow central hinge body (5), adapted to be coupled to a second body (6), which is also internally hollow and is adapted to be coupled to an eyeglasses temple (3), and to a third body (12) adapted to be coupled to the front of the eyeglasses, it being possible to assemble the central body and the second and third body in a pack, in order to define internally the passage of a data/power cable (20), the central body (5) allowing an accumulation of the data/power cable (20) and ensuring the passage of the cable (20) between the temple (3) and the front (4) without stretching and/or torsion.