Multi-Jointed Folding Eyeglasses for Compact Low-Effort Storage

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Solution Overview

Problem

Existing folding eyeglasses do not achieve the smallest possible space occupation and require significant effort to fold, with limitations in both temple and front-level folding mechanisms.

Innovation Solution

The eyeglasses feature a multi-jointed hinge system with differentially loaded compression springs and bistable mechanisms allowing temples and front to be folded with minimal effort, achieving a compact configuration by superimposing lenses and temples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If existing folding mechanisms are used, then the eyeglasses can be folded, but the space occupation and folding effort are not optimized

Engineering Contradiction:
Improvespace occupationVSAvoidfolding effort
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The temple is divided into multiple segments including a proximal temple portion, a distal temple portion, and an intermediate temple portion. This segmentation allows each part to fold independently and contribute to achieving the compact folded state while distributing the folding action across multiple joints, reducing the effort required at each individual joint.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The folding mechanism is designed so that the distal temple portion nests within the proximal temple portion when folded, and the intermediate temple portion provides additional nesting capability. This nested configuration minimizes the overall volume occupied by the folded eyeglasses while maintaining ease of operation through the progressive folding action.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Length of stationary object

If simple folding mechanisms are used, then the device complexity is low, but the folding thickness is not minimized

Engineering Contradiction:
Improvefolding thicknessVSAvoidfolding mechanism complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The front is divided into a first front portion and a second front portion, creating a bi-stable hinge mechanism that enables the front to fold onto itself. This segmentation allows the lenses to be superimposed, minimizing the folding thickness while keeping the mechanism relatively simple through the use of standard hinge components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bi-stable hinge mechanism provides dynamic folding capability where the front can transition between open and folded states. This dynamic design allows the front to actively engage in the folding process, reducing the overall folding thickness without requiring complex mechanical systems.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If multi-jointed hinges with springs are used, then the folding effort is reduced, but the device complexity increases

Engineering Contradiction:
Improvefolding effortVSAvoidhinge mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Compression springs are incorporated into the multi-jointed hinge mechanism to provide counterbalancing force that assists the user during folding and unfolding operations. The springs store and release mechanical energy, reducing the effort required by the user while adding only moderate complexity through the integration of spring elements within the hinge assembly.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The multi-jointed hinge with integrated springs creates a dynamic system that adapts to the folding motion. The springs provide progressive resistance and assistance throughout the folding range, making the operation easier while the modular joint design keeps the overall complexity manageable through standardized components.

Inventive Principle:
Principle #15Dynamics

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 eyeglasses can be folded to occupy the smallest possible space with minimal user effort, ensuring high reliability and competitive costs.

Implementation Method 1

there are compression springs arranged between said sliders and the respective temple portions

Methodology Applied
Scientific EffectElastic potential energy storage and release: Spring

Implementation Method 2

The temple is provided with a bi-stable hinge mechanism which enables said temple to be folded onto itself

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4237904B1Folding eyeglasses
Publication Date: 2025.12.31 LUXOTTICA SRL
  • EP4237904B1 patent drawingFigure 1
  • EP4237904B1 patent drawingFigure 2a~2b
  • EP4237904B1 patent drawingFigure 3

AI summary

Folding eyeglasses (1), comprising a front (2) which supports a pair of lenses (3) and a pair of temples (4) hinged to the front (2), each one of the temples (4) comprises a proximal portion (4a) and a distal portion (4b) which are mutually hinged by means of a hinge (5); the hinge (5) comprises a multi-jointed central body (6) configured to allow a first 90° rotation of the distal portion (4b) of the temple (4) and a further 90° rotation of the multi-jointed central body (6) with respect to the proximal portion (4a) of the temple (4), in order to arrange the proximal portion (4a) of the temple (4) and the distal portion (4b) of the temple so that they are mutually parallel and superimposed.