Eyeglass Temple Leaf Spring Threshold Mechanism

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Solution Overview

Problem

Eyeglass temples made of flat metal sheet tend to expand spontaneously due to spring force, leading to erratic and unexpected movements, which can cause them to 'leap up' during storage or retrieval, potentially causing injuries and getting stuck in pockets.

Innovation Solution

Incorporating a central leaf spring with a recess on its internal surface that engages with the connection element's counter surface, creating a threshold to inhibit spontaneous expansion, requiring a controlled manual force to expand or fold the temple, thus preventing self-sliding motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the central leaf spring slides freely on the counter surface without resistance, then the temple can fold smoothly, but the temple may expand spontaneously and leap up during storage or retrieval

Engineering Contradiction:
Improvesmooth folding motionVSAvoidspontaneous expansion control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a threshold element that changes the friction parameter between the leaf spring and counter surface. The threshold provides high sliding resistance to prevent spontaneous expansion while allowing controlled manual expansion when sufficient force is applied. This parameter change resolves the contradiction by making the sliding resistance conditional rather than constant.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a threshold is introduced to prevent spontaneous expansion, then the temple remains stable during storage, but the temple requires increased force to expand manually

Engineering Contradiction:
Improvestability during storageVSAvoidforce required for expansion
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The threshold element applies preliminary anti-action by creating a barrier that must be overcome before expansion can occur. This preliminary resistance prevents spontaneous movement during storage while still allowing intentional expansion when the user applies sufficient manual force. The threshold acts as a gatekeeper that distinguishes between accidental and intentional expansion.

Inventive Principle:
Principle #9Preliminary anti-action

3Shape

If the leaf spring material is made thinner to achieve filigree design, then the eyeglasses become more delicate and lightweight, but the sliding contact becomes insufficient to keep the temple closed

Engineering Contradiction:
Improvefiligree designVSAvoidsliding contact sufficiency
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The threshold element serves as an intermediary between the thin leaf spring and the counter surface. It compensates for the insufficient sliding contact inherent in thin filigree designs by providing a mechanical barrier that prevents spontaneous expansion. The threshold mediates the interaction between the delicate leaf spring structure and the requirement for reliable temple retention.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively prevents the temple from leaping up by increasing sliding resistance, ensuring that manual actuation is required for both expansion and folding, maintaining a smooth external surface and allowing for easy manufacturing even with thin material.

Implementation Method 1

the central leaf spring of the temple slides with a sliding surface on a counter surface provided on the free end of the connection element, the central leaf spring having a threshold which will hamper continuous motion of it

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2614402B1Eyeglass frame and temple
Publication Date: 2020.01.15 IC BERLIN BRILLENPRODUKTIONS GMBH
  • EP2614402B1 patent drawingFigure 1a~1b
  • EP2614402B1 patent drawingFigure 2a~2b

AI summary

The present invention relates to an eyeglass temple (1) and an eyeglass frame wherein the eyeglass temple (1) has at least two leaf springs (3; 4; 5). For preventing free sliding motion of the eyeglass temple means (15; 16; 17;18; 20; 25) are provided which are realized such that they are able to inhibit said free sliding motion.