Eyeglass Hinge Device Using Elastic Deformation Locking

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Solution Overview

Problem

Conventional hinge devices for eyeglasses suffer from structural mechanical weak points, such as screws that can unscrew easily, requiring precise machining, leading to increased size, weight, and reduced friction over time, which results in a less effective and more costly design.

Innovation Solution

A compact hinge device with an accommodation body and C-shaped hollow bodies that utilize engagement teeth and washers made from flexible materials to provide secure locking and friction, eliminating the need for external screws and ensuring a lightweight, minimal design with improved mechanical reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional hinge devices use screws and welds to couple the temple to the end piece, then the structure provides mechanical coupling, but it creates structural mechanical weak points and increases the size and weight of the hinge device

Engineering Contradiction:
Improvemechanical coupling strengthVSAvoidhinge device weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent removes the screw from the hinge device structure, replacing it with a deformation-based locking mechanism. The tongue element is inserted into the accommodation body and locked through elastic deformation of the engagement elements, eliminating the need for separate fastening components like screws that add weight and create weak points.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional mechanical screw-thread system with an elastic deformation-based locking system. Instead of using threaded engagement, the invention uses flexible engagement elements that deform elastically to lock the tongue element in place, reducing the number of parts and overall weight.

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

2Ease of operation

If conventional hinge devices use screws that are accessible from outside the end piece, then the structure allows for assembly and disassembly, but it increases the size of the hinge device and contributes to a less minimal design

Engineering Contradiction:
Improveassembly and disassembly capabilityVSAvoidhinge device size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent extracts the screw from the visible external structure, hiding all fastening mechanisms within the accommodation body. The tongue element is accessed through the temple itself, keeping the end piece clean and minimal while maintaining the ability to assemble and disassemble the hinge device.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent nests the fastening mechanism within the accommodation body, which is itself integrated into the end piece structure. The tongue element is inserted through the temple and locked within the accommodation body, creating a nested arrangement that minimizes external dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Force

If conventional hinge devices rely on screw friction to provide resistance to temple opening, then the mechanism provides initial friction, but the screw tends to become stripped over time and the friction becomes less effective

Engineering Contradiction:
Improvefriction resistanceVSAvoidfriction effectiveness over time
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent uses elastic deformation of the engagement elements as a consumable mechanism. The elastic material gradually loses its ability to deform and return to its original shape over time, providing a built-in wear indicator. When the elastic elements no longer provide sufficient friction, the hinge device needs to be replaced, ensuring reliable operation throughout its service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the physical state of the engagement elements from rigid (as in screw-based systems) to flexible and elastic. This allows the friction characteristic to evolve over time as the material deforms, providing consistent resistance during the functional life of the device and clear indication when replacement is needed.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If conventional hinge devices use precise mechanical machining to create threads for screws, then the structure provides accurate screw engagement, but it increases manufacturing costs and complexity

Engineering Contradiction:
Improvethread accuracyVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the precision-machined thread system with a deformation-based locking mechanism. The engagement elements are formed through stamping or molding processes that create flexible structures capable of elastic deformation, eliminating the need for complex threading operations and reducing manufacturing precision requirements.

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

Solution Approach 2:

The patent employs materials with specific elastic properties that allow the engagement elements to deform and lock without requiring precise mechanical machining. The use of elastomeric or spring-like materials enables simple forming processes while achieving reliable mechanical coupling.

Inventive Principle:
Principle #40Composite materials

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 results in a lightweight, reliable, and cost-effective hinge device with enhanced resistance to temple opening and closing, reducing the risk of mechanical failures and maintaining effective friction over time.

Implementation Method 1

a second C-shaped hollow body (2) which defines an accommodation body (2) and which is provided with retention teeth (17) that make it possible to lock the teeth (7) of the first C-shaped hollow body (4)... an elastic element that makes it possible to lock the tongue element (3) to the accommodation body (2) in a detachable manner

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

washers (10) which are adapted to be inserted along the hinging axis, are made of polymeric or metallic material and are arranged symmetrically so as to interpose themselves between the eyelets (9) and the eyelet (5a)... the friction necessary for the temple of the eyeglass frame to be able to be opened while offering a certain resistance

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3146381B1Hinge device for eyeglasses
Publication Date: 2024.05.01 LUXOTTICA SRL
  • EP3146381B1 patent drawingFigure 1~2
  • EP3146381B1 patent drawingFigure 3~4
  • EP3146381B1 patent drawingFigure 5

AI summary

A hinge device (1) for eyeglasses, which comprises an accommodation body (2) provided with engagement seats for gripping and locking a hinge body (3) to an end piece (15) of an eyeglass frame, the hinge body (3) comprising a central body (4) that is adapted to engage within the accommodation body (2), the central body (4) being adapted to engage in turn a temple (5) of the eyeglass frame.