Asymmetrical Column Wheel for Chronograph Lever Control
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Solution Overview
Problem
Conventional column wheels in chronograph watches experience excessive force transmission to levers, leading to increased friction, wear, and suboptimal precision in managing chronograph functions due to their symmetrical truncated triangle cross-section design.
Innovation Solution
A column wheel with asymmetrical columns, where the leading edge is more angled than the trailing edge, allowing for a better distribution of forces and precision in lever operation, featuring a hub and arms that are 10-50% the height of the columns, enabling extended lever stroke and optimized mechanical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional symmetrical truncated triangle columns are used, then manufacturing is simple and inexpensive, but excessive forces are transmitted to levers causing increased friction and wear
Solution Approach 1:
The column cross-section is designed as an asymmetrical quadrilateral rather than a symmetrical truncated triangle. The asymmetry allows optimization of force transmission characteristics to levers, reducing excessive forces while maintaining manufacturing feasibility through standardized machining processes.
Solution Approach 2:
Different sides of the column cross-section have different geometric properties tailored to specific functions: the leading edge has optimized angles for force distribution, while other sides maintain structural integrity. This localized optimization reduces friction and wear on specific lever contact points without compromising overall column strength.
2Ease of manufacture
If conventional symmetrical columns are used, then manufacturing is straightforward, but precision in chronograph function management is suboptimal
Solution Approach 1:
The asymmetrical quadrilateral cross-section with specifically optimized angles (such as 45-60 degrees for the leading edge) enables more precise control over lever activation and chronograph function timing, improving measurement precision while remaining manufacturable.
3Length of moving object
If column height is increased to improve lever stroke, then lever stroke is extended, but forces on levers become more excessive
Solution Approach 1:
The optimized quadrilateral cross-section with specific angle ranges (45-60 degrees for leading edge, 30-45 degrees for trailing edge) distributes forces more evenly along the column length, allowing extended lever stroke without proportionally increasing forces on lever contact points.
Data Source
Figure 1~2
Figure 3~4
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AI summary
The invention relates to a column wheel (1) for a chronograph, comprising: a ratchet (2) provided with a plurality of teeth (3), the shape of which defines a rotational axis for the column wheel; a superstructure coaxial to the wheel and having rotation symmetry of around n >= 3, the peripheral portion of the superstructure defining n columns (10) parallel to the wheel axis and arranged substantially along the edge of the ratchet (2), each column having an outer portion with a cross-section substantially shaped like a truncated triangle with a base substantially parallel to the circumference of the wheel and a front side (12), referred to as a leading edge, and a rear side (13), referred to as a trailing edge, extending from the base towards the inside of the wheel. The column wheel is characterised in that said cross-section is asymmetrical, with a first angle a between the leading edge (12) and the base (14) being lower than a second angle ß between the base and the trailing edge (13).