T-Shaped Column Wheel for Chronograph Mechanism
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Solution Overview
Problem
Existing chronograph mechanisms require complex and varied shapes for pivoting control parts, leading to increased production costs and mechanical stress due to the need for precise alignment and shaping, which complicates standardization and reduces the length available for lever travel.
Innovation Solution
A three-stroke column wheel with four regularly distributed columns and a hub, connected by arms, providing a more rigid structure with tapered columns and arms that allow for extended lever travel and reduced mechanical stress, fabricated entirely on a lathe for precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the beaks of pivoting control parts are given complex shapes to achieve precise alignment with columns, then measurement precision is improved, but device complexity increases and manufacturing precision requirements worsen
Solution Approach 1:
The columns are designed with an asymmetric T-shaped cross-section rather than symmetric conventional shapes. This asymmetric geometry enables precise alignment and activation of the pivoting control parts' beaks through the column's inherent geometric properties, eliminating the need for complex beak shaping while maintaining high measurement precision.
Solution Approach 2:
The invention changes the geometric parameters of the columns (T-shaped cross-section with specific width and height relationships) to achieve the desired precision. By optimizing the column dimensions and shape parameters, the system achieves precise lever activation without requiring complex corresponding features on the pivoting control parts.
2Reliability
If the beaks of pivoting control parts are made wider to ensure proper engagement, then reliability is improved, but the length available for lever travel decreases, worsening the force requirements
Solution Approach 1:
The T-shaped column provides inherent geometric engagement features that ensure reliable activation without requiring wide beaks. The asymmetric geometry creates a natural engagement interface that maintains reliability while preserving lever travel length.
Solution Approach 2:
The solution moves the engagement precision requirement from the horizontal dimension (beak width) to the vertical dimension (column height and shape). This dimensional shift allows narrow beaks to achieve precise engagement through the column's vertical geometric features, maintaining both reliability and lever travel length.
3Ease of manufacture
If conventional column shapes are used that require trimming cutters, then ease of manufacture is improved, but manufacturing precision worsens due to the complexity of sculpting columns
Solution Approach 1:
The T-shaped column geometry is specifically designed to be manufacturable by standard turning operations on a lathe. The asymmetric shape consists of cylindrical and conical sections that are routine lathe operations, eliminating the need for complex trimming cutter operations while achieving high manufacturing precision.
Solution Approach 2:
The invention replaces the trimming cutter sculpting process with standard lathe turning operations. This substitution of manufacturing methods simplifies the fabrication process while improving precision, as lathe operations are more controllable and repeatable than complex trimming cutter operations.
Data Source
AI summary
The column wheel (40) for a 3 stroke mechanism has a hub (46) arranged at the centre of a superstructure exhibiting rotational symmetry of order n, the superstructure including n radial arms (48) and n columns (44) parallel to the axis of rotation of the column wheel, the columns being regularly distributed along the circumference of the column wheel and separated from each other by n empty spaces forming as many openings between the columns. The column wheel is characterized in that the width of the columns (44) is larger than the openings between the columns, and in that the width of the arms (48) is less than half the width of the columns (44).