Watch Movement Clamping via Elastomeric Stress Absorption

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Solution Overview

Problem

Existing methods for securing a watch movement in a housing are complex, inefficient, and prone to deformation, especially under pressure or temperature variations, which can cause torsional stress on the movement, and are not suitable for large-scale production or maintaining aesthetic transparency.

Innovation Solution

A timepiece design featuring a case with a middle part and a clamping element that compresses the movement between its lower and upper peripheral bearing surfaces, using an annular peripheral shoulder and a hollowed central part to absorb deformations and reduce torsional stress, allowing for assembly from the dial side without turning the case, thus simplifying the assembly process and increasing productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flanges and screws are used to fix the movement to the case, then the fixing is reliable and reversible, but the complexity of implementation increases and productivity decreases

Engineering Contradiction:
Improvefixing reliabilityVSAvoidassembly productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention extracts the screw-fixing operation from the assembly process by providing a movement with an integrated fixing structure (protrusion and recess) that enables direct mechanical interlocking without screws or flanges, thereby eliminating the complex handling operations while maintaining reliable and reversible fixing

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediate fixing structure consisting of a protrusion on the movement and a corresponding recess in the case band, which acts as a mediator between the movement and the case, enabling simple yet reliable mechanical attachment without requiring screw operations

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the movement is fixed by driving in with intermediate parts, then assembly is simplified, but the case bottom must match the movement shape to exact machining tolerances

Engineering Contradiction:
Improveassembly easeVSAvoidmachining tolerance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention segments the fixing function into two complementary parts: a protrusion on the movement and a recess in the case band, allowing each part to be manufactured independently with standard tolerances while achieving precise alignment and secure fixing when assembled, thereby reducing overall manufacturing precision requirements

Inventive Principle:
Principle #1Segmentation

3Reliability

If the case bottom is made to match the movement shape to exact tolerances, then the movement is securely held, but any deformation of the bottom is replicated on the movement plate causing damage

Engineering Contradiction:
Improvemovement retentionVSAvoiddeformation stress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention introduces a compliant intermediate layer (elastomeric material) between the case bottom and the movement plate that acts as a mediator, absorbing deformations and stresses from the case bottom while maintaining secure retention of the movement, thereby preventing transmission of harmful deformations to the movement plate

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention employs a flexible elastomeric material in the case bottom that can deform independently of the rigid movement plate, allowing the bottom to accommodate pressure and temperature variations without transmitting stress to the movement, thereby protecting the movement from deformation damage

Inventive Principle:
Principle #30Flexible shells and thin films

4Stability of the object's composition

If reinforced structures with metal skeletons are used to stiffen the case, then deformation is prevented, but aesthetic properties and transparency are compromised

Engineering Contradiction:
Improvecase stiffnessVSAvoidaesthetic transparency
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The invention uses a flexible elastomeric material that can be made transparent or translucent, providing the necessary structural support and deformation absorption without requiring opaque metal reinforcements, thereby maintaining the aesthetic transparency of the case while preventing harmful deformations

Inventive Principle:
Principle #30Flexible shells and thin films

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 design effectively absorbs deformations and reduces torsional stress on the movement, enhancing the robustness and durability of the connection while maintaining aesthetic integrity and improving assembly efficiency.

Implementation Method 1

The bottom comprises an elastomeric material and a central part hollowed out in which the movement is received when assembled in the case

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a clamping element bearing against an upper peripheral bearing surface of the movement, such that the movement is compressed between its lower peripheral bearing surface and its upper peripheral bearing surface

Methodology Applied
Scientific EffectMechanical compression: Compression

Data Source

PatentEP2989505B1Method for attaching a movement inside a case
Publication Date: 2017.05.03 ETA SA MFG HORLOGERE SUISSE
  • EP2989505B1 patent drawingFigure 1
  • EP2989505B1 patent drawingFigure 2A~2B

AI summary

Timepiece comprising a case in which is housed a movement comprising a lower peripheral bearing surface, the case comprising a case middle with which are assembled respectively a back and a crystal. The timepiece is characterized in that it further comprises a clamping element provided with a lower retaining surface and that the movement comprises an upper peripheral bearing surface, the lower retaining surface of the clamping element and the upper peripheral bearing surface being in contact with one another, and in that the back comprises an annular peripheral shoulder against which the lower peripheral bearing surface of the movement rests, which movement is compressed between the lower peripheral bearing surface thereof and the upper peripheral bearing surface thereof by the annular peripheral shoulder of the back and the lower retaining surface of the clamping element, respectively.