Tiltable Tracing Stylus Shaft for Eyeglass Frame Measurement

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Solution Overview

Problem

Existing eyeglass frame shape measurement apparatuses face challenges in accurately measuring highly curved frames without the tracing stylus dropping out of the groove, and in coping with various frame shapes, often resulting in reduced measurement accuracy due to excess force application and increased mechanism size.

Innovation Solution

The apparatus employs a tiltable tracing stylus shaft with a measurement pressure application mechanism, allowing the stylus to follow the rim's curvature smoothly while minimizing the risk of dropping out, using a combination of XYZ directional movement and tilt control to maintain contact with the frame's groove.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a tracing stylus with a needle-like tip end is used to follow changes in the rim, then the tracing stylus can accurately trace highly curved frames, but the tracing stylus may drop out of the groove

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidstylus retention in groove
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The tracing stylus shaft is made tiltable rather than fixed, allowing it to dynamically adjust its angle to follow the curvature of the rim. The shaft can tilt within a predetermined angle range to maintain contact with the groove while accommodating highly curved frames, preventing the stylus from dropping out.

Inventive Principle:
Principle #15Dynamics

2Reliability

If an arm with a tracing stylus attached is tilted to follow changes in the rim, then the tracing stylus can maintain contact with the groove, but the arm has to be long and the mechanism increases in size

Engineering Contradiction:
Improvecontact maintenanceVSAvoidmechanism size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of tilting the entire long arm, only the tracing stylus shaft is made tiltable. This localized tilting capability allows the stylus to follow rim curvature changes while keeping the main arm structure compact and reducing overall mechanism size.

Inventive Principle:
Principle #3Local quality

3Reliability

If the tracing stylus shaft is made tiltable to follow the rim curvature, then the stylus can maintain contact without dropping out, but the mechanism becomes more complex

Engineering Contradiction:
Improvestylus retentionVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tracing stylus shaft is made tiltable rather than fixed, allowing it to dynamically adjust its angle to follow the curvature of the rim. The shaft can tilt within a predetermined angle range to maintain contact with the groove while accommodating highly curved frames, preventing the stylus from dropping out.

Inventive Principle:
Principle #15Dynamics

4Reliability

If an urging mechanism is used to press the tracing stylus into the groove, then the stylus maintains contact with the rim, but excess force may deform the rim

Engineering Contradiction:
Improvecontact maintenanceVSAvoidrim deformation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The urging force applied by the spring is carefully controlled to be within a predetermined range. This optimized force parameter is sufficient to maintain stylus contact with the groove while being gentle enough to prevent deformation of the rim, especially important for highly curved frames.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2335873B1Eyeglass frame shape measurement apparatus
Publication Date: 2019.02.27 NIDEK CO LTD
  • EP2335873B1 patent drawingFigure 1~2
  • EP2335873B1 patent drawingFigure 3~4
  • EP2335873B1 patent drawingFigure 5

AI summary

An apparatus for measuring a shape of an eyeglass frame, includes: a tracing stylus moving unit that includes a tracing stylus detecting a position of a rim of the frame in a moving radius direction and in a vertical direction, a tracing stylus shaft for the tracing stylus, a holding unit configured to vertically-movably hold the tracing stylus shaft, a vertical direction moving unit for moving the holding unit in the vertical direction, and a moving radius direction moving unit for moving the holding unit in the moving radius direction so that the tracing stylus traces the rim; a vertical position detection unit for detecting a position of the tracing stylus in the vertical direction; and a controller for obtaining a next measurement position of the holding unit in the vertical direction based on the detecting result of the vertical position detection unit, and controls the vertical direction moving unit.