Eyeglasses Frame Cam Hinge for Stable Temple Positioning

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Solution Overview

Problem

Conventional eyeglasses frames with hinges face challenges in achieving stable open/close operations while reducing size and weight, as the friction-based pivot mechanism leads to unstable temple movement and requires frequent adjustments, and incorporating elastic biasing means increases hinge size and weight.

Innovation Solution

The design incorporates a cam-shaped first hinge barrel with specific depressions and a non-rotatable second screw that stabilizes the temple's open and closed positions without a spring, allowing for reduced hinge size and weight by using a cam mechanism to control the temple's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a screw is tightened firmly to increase friction between hinge barrels, then the temple pivoting becomes stable, but the temple pivoting becomes stiff and smooth open/close operation cannot be realized

Engineering Contradiction:

Improvestability of temple positioningVSAvoidsmoothness of open/close operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The hinge barrel is segmented into multiple functional surfaces: a first inclined surface for smooth closing, a second inclined surface for smooth opening, and a flat surface for stable positioning. This segmentation allows each surface to perform its specific function independently, resolving the contradiction between smooth operation and stable positioning.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The hinge mechanism transitions from a static friction-based system to a dynamic cam-based system. The cam profile dynamically guides the temple through different phases: smooth closing on the first inclined surface, stable positioning on the flat surface, and smooth opening on the second inclined surface. This dynamic approach eliminates the need for high friction while maintaining stability.

Inventive Principle:

Principle #15Dynamics

2Reliability

If elastic biasing means (spring) is incorporated in the hinge to stabilize open/close positions, then stable positioning is achieved, but the size and weight of the hinge increase

Engineering Contradiction:

Improvestability of open/close positionsVSAvoidweight of hinge

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The spring (elastic biasing means) is extracted from the hinge mechanism and replaced with a cam-based positioning system. The cam profile inherently provides stable positioning through its geometric design, eliminating the need for additional components like springs, thereby reducing weight and size.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The cam mechanism is self-servicing in that it provides both the driving force for open/close operation and the positioning stability without requiring separate elastic biasing means. The geometric shape of the cam itself serves the dual function of motion control and position stabilization.

Inventive Principle:

Principle #25Self-service

3Reliability

If elastic biasing means (spring) is incorporated in the hinge to stabilize open/close positions, then stable positioning is achieved, but the size of the hinge increases limiting design freedom

Engineering Contradiction:

Improvestability of open/close positionsVSAvoidsize of hinge

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The positioning function previously requiring a separate spring mechanism is merged into the cam profile itself. The cam's geometric design integrates both the motion control function and the positioning stability function into a single component, reducing overall hinge size and complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Inventive Principle:

Principle #25Self-service

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

This solution enables stable open/close operations without the need for a spring, reducing the hinge's size and weight, thereby enhancing design flexibility and user experience.

Implementation Method 1

a cam that is a cam of a tip portion of the first hinge barrel and includes a first depression where the second screw comes to rest when the eyeglasses frame is completely open, a second depression where the second screw comes to rest when the eyeglasses frame is completely closed

Methodology Applied

Scientific EffectCam mechanism: Cam

Data Source

PatentUS9946091B2Eyeglasses frame

Publication Date: 2018.04.17 KAWAMOTO KOGAKU INDS

AI summary

The eyeglasses frame includes a first hinge barrel provided on a lens holding portion, a second hinge barrel provided on a temple, a first screw that pivotably couples the first hinge barrel and the second hinge barrel, and a second screw provided in the second hinge barrel and contactable with the first hinge barrel. A tip portion of the first hinge barrel is a cam that includes a first depression where the second screw comes to rest when the eyeglasses frame is completely open, a second depression where the second screw comes to rest when the eyeglasses frame is completely closed, substantially straight portions that join the first and second depressions, and a corner portion where the substantially straight portions change direction at a point therebetween.