Magnetism Sensor Timepiece Spring Rods Using Non-Magnetic Materials

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Solution Overview

Problem

Magnetism sensors in timepieces are affected by magnetic fields from materials like stainless steel spring rods and bands, leading to inaccurate orientation measurements.

Innovation Solution

Using titanium-based materials for spring rods and non-magnetic cobalt-nickel alloy springs to minimize magnetization, along with non-metal bands and cover members to prevent direct contact and reduce magnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spring rods are made of stainless steel (SUS material), then structural strength and elasticity are ensured, but magnetization occurs affecting magnetism sensor accuracy

Engineering Contradiction:
Improvestructural strengthVSAvoidorientation measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the material parameter of spring rods from stainless steel to titanium-based material. This parameter change maintains the necessary mechanical properties (strength and elasticity) while fundamentally altering the magnetic properties to be non-magnetic, thereby resolving the contradiction between structural reliability and measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If spring rods are made of non-magnetic material (titanium), then magnetism sensor accuracy is improved, but weight reduction is achieved as a secondary benefit

Engineering Contradiction:
Improveorientation measurement accuracyVSAvoidspring rod weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent applies material substitution by changing from stainless steel to titanium-based material. This parameter change primarily solves the measurement precision issue by eliminating magnetization, while simultaneously achieving weight reduction as an additional benefit, thus resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If timepiece band and connecting parts are made of magnetic material, then manufacturing cost and ease of manufacture are reduced, but magnetism sensor operation is affected

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmagnetism sensor operation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the material parameter of the timepiece band and connecting parts from magnetic materials to non-magnetic materials. This parameter change ensures the reliable operation of the magnetism sensor by preventing magnetization, while still allowing for practical manufacturing solutions.

Inventive Principle:
Principle #35Parameter changes

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

Ensures accurate orientation detection by avoiding magnetization effects, reducing weight, and lowering production costs while enhancing wearability and exterior appearance.

Implementation Method 1

the spring rods, which link the band to the bows of the case of the timepiece, are each formed of the pipe and the pin, which are each made of titanium... a situation in which the spring rods are magnetized and affects the magnetism sensor can be avoided

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 2

the spring, which is made of a non-magnetic material that has elasticity and is unlikely to be magnetized, such as a cobalt-nickel alloy

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the spring, which is made of a non-magnetic material that has elasticity and is unlikely to be magnetized

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP3460589B1Magnetism sensor equipped timepiece
Publication Date: 2020.08.19 SEIKO EPSON CORP
  • EP3460589B1 patent drawingFigure 1
  • EP3460589B1 patent drawingFigure 2
  • EP3460589B1 patent drawingFigure 3

AI summary

A magnetism sensor equipped timepiece includes a case including a built-in magnetism sensor, a band for the timepiece, and spring rods that attach the band to bows of the case. The spring rods are each formed of a pipe, a pin, and a spring. The pipes and the pins are each made of a non-magnetic material, and the springs are made of a non-magnetic material having elasticity.