Suspended Membrane Spring Shock-Absorbing Bearing

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Solution Overview

Problem

Current anti-shock systems in timepieces, such as the inverted double-cone device, suffer from suboptimal damping and recentering due to friction between components, leading to inefficient shock absorption and potential blocking of the bezel's return to its initial position.

Innovation Solution

A shock-absorbing bearing system utilizing a suspended membrane spring with elastic means, eliminating contact and friction between the spring and support, and made from materials like polymers or metals for enhanced shock absorption and reduced manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional spring with radial extensions is used to hold the jewels, then the shock absorption function is provided, but friction occurs between the spring and the support which slows or blocks the recentering movement

Engineering Contradiction:
Improveshock absorption reliabilityVSAvoidfriction between spring and support
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The harmful friction contact between the spring and support is completely eliminated by extracting the support contact function. The spring is made suspended with no contact points to the support, removing the source of friction while maintaining shock absorption through the spring's elastic deformation alone

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A polymer layer is introduced as an intermediary between the spring and the support. This layer allows the spring to be held in position without direct metal-to-metal contact, eliminating friction while maintaining the structural relationship and shock absorption function

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the spring is dimensioned with a displacement limit to allow balance shaft contact with stops, then shock absorption is achieved, but the pivot pins cannot absorb shock without breaking

Engineering Contradiction:
Improveshock absorption capabilityVSAvoidpivot pin strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The spring is pre-configured with optimal elastic properties to absorb shock energy before it can transmit to the pivot pins. By tuning the spring's displacement limit and elastic modulus, the system cushions shocks in advance, preventing force transmission that would break the pins

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If traditional cutting methods are used to manufacture the spring, then the spring can be made from phynox, CuBe, or brass, but the manufacturing process is complex and costly

Engineering Contradiction:
Improvespring performanceVSAvoidspring manufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The spring material is changed from traditional metals (phynox, CuBe, brass) to polymer, fundamentally changing the manufacturing parameters. This allows transition from precision cutting methods to molding processes, simplifying manufacturing while maintaining or improving spring performance through polymer's inherent elasticity and friction properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention accepts that the spring may have a limited service life but compensates by making it inexpensive to manufacture. Polymer springs can be produced cheaply through molding, allowing replacement without significant cost while maintaining reliable shock absorption during their service life

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

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 system achieves perfect recentering without friction, simplifies manufacturing, and reduces costs while providing improved shock resistance and durability through the use of materials with high deformation capacity and low friction coefficients.

Implementation Method 1

The shock-absorbing system comprises elastic means arranged to exert at least one axial force on said pivot system

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A shock-absorbing bearing system utilizing a suspended membrane spring with elastic means, eliminating contact and friction between the spring and support

Methodology Applied
Scientific EffectShock absorption: Damping

Data Source

PatentEP2791741B1Shockproof system with membrane for timepieces
Publication Date: 2020.06.24 ETA SA MFG HORLOGERE SUISSE
  • EP2791741B1 patent drawingFigure 1~3
  • EP2791741B1 patent drawingFigure 4~6
  • EP2791741B1 patent drawingFigure 7~8

AI summary

The invention relates to a shock-absorbing bearing for a shaft (3, 103) of a train of a timepiece, wherein said shaft includes a pivot shank (3a, 103a) and said bearing comprises a mounting (1, 101) provided with a recess (6, 106) for receiving a pivot system (105) including a pivot module (109) in which the pivot shank is inserted, and resilient means (107) arranged so as to enable said pivot module to be mounted so as to be suspended, and so as to exert at least axial force onto said pivot module. The resilient means includes a diaphragm spring.