Clockwork Column Wheel Shaft Stability

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Solution Overview

Problem

Existing watch movements with chronograph functions, particularly those using column wheels, face challenges in precision and durability due to uneven stress distribution and complex assembly, which affect the accuracy and longevity of the movement.

Innovation Solution

A watch movement design where the control member is mounted on a shaft with two bearings arranged on either side of the frame, allowing for balanced stress distribution and improved stability, eliminating cantilever configurations and enhancing precision and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the column wheel is mounted on a single bearing or tenon, then the structure is simpler, but the stress distribution is uneven and positioning precision deteriorates over time

Engineering Contradiction:
Improvemounting structure complexityVSAvoidcolumn wheel positioning precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The single bearing mounting is segmented into two bearings arranged on opposite sides of the frame. This segmentation distributes the mechanical stresses from the control lever across two separate support points, preventing the uneven stress concentration that occurs with single-point mounting and thereby maintaining positioning precision over time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two bearings are positioned to create a balanced support structure that counteracts the forces applied to the control member. By placing bearings on opposite sides of the frame, the structure creates a counterbalancing effect that distributes loads evenly, preventing the cumulative positioning errors that occur with unbalanced single-point mounting.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Ease of manufacture

If the control member is mounted with a single bearing, then the assembly is simpler, but the reliability and resistance to wear over time deteriorates

Engineering Contradiction:
Improveassembly simplicityVSAvoidmovement reliability over time
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The mounting system is divided into two separate bearings instead of one, creating redundant support points. This segmentation ensures that wear or failure at one bearing does not immediately compromise the entire control mechanism, thereby improving long-term reliability while maintaining reasonable assembly simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dual bearing arrangement provides beforehand cushioning against wear and mechanical failure. By distributing the load across two bearings, the system preemptively reduces the stress on each individual bearing, slowing wear rates and extending the operational life of the control member before failure would occur.

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

3Volume of moving object

If the control member is mounted on a single bearing, then the device is less bulky, but the flexibility in arranging mechanisms deteriorates

Engineering Contradiction:
Improvemovement volumeVSAvoidmechanism arrangement flexibility
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The control member is positioned in three-dimensional space between two bearings rather than being constrained to a single mounting point. This dimensional arrangement allows the controlled mechanisms to be distributed throughout the movement volume, providing greater flexibility in mechanism placement while maintaining a compact overall size.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The dual bearing mounting creates a universal support structure that can accommodate multiple different mechanism arrangements. The control member can effectively control mechanisms positioned at various locations and orientations, making the movement design more versatile without significantly increasing the overall volume.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP1960846B1Clockwork movement
Publication Date: 2012.10.17 COMPLITIME SA
  • EP1960846B1 patent drawingFigure 1a~1b
  • EP1960846B1 patent drawingFigure 2~3
  • EP1960846B1 patent drawingFigure 4

AI summary

The invention relates to a clockwork movement comprising a control member actuatable by a control lever (20) in response to a user's action and embodied in the form of a column wheel (40). Said control member is rotatably mounted on the clockwork movement frame around an axis X, which is perpendicular thereto, for controlling first and second mechanisms exhibiting at least one movement function such as chronograph or alarm function. For this purpose, the control member comprises rotationally fixable first, second and third parts (35, 4, 45, 53) which are mounted on a shaft (41) at first, second and third levels, respectively, in a direction of the axis X for interacting with the control lever and for controlling said mechanisms. In addition, the shaft (41) which is pivotally mounted with respect to the frame is arranged in at least two bearings (49, 51), which are positioned remotely to each other for ensuring the shaft good stability, whereas the second and third parts are located on the both parts of the frame. In the preferred inventive embodiment, the end of the shaft (41) opposite to the control member is provided with a square (42) onto which a sleeve (43) bearing the third part is engaged.