Asymmetrical Ribs in Flexible Guide Pivots
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Solution Overview
Problem
Traditional mechanical watch oscillators face precision limitations due to friction differences in pivot positions, leading to non-linearity in bending angle and moment relationships, which result in errors such as 100 seconds per day, and existing solutions either fail to control or cancel anticlastic curvature effectively, limiting guiding and manufacturing simplicity.
Innovation Solution
A rotary flexible guide pivot with asymmetrical ribs distributed along the flexible strips to inhibit anticlastic curvature, facilitating easier manufacturing and improved isochronism by minimizing surface intersection and simplifying strip separation, while maintaining elastic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single flat flexible strip is used as a rotary flexible guide, then the structure is simple and manufacturing is easy, but anticlastic curvature causes non-linearity in the bending angle and moment relationship, resulting in chronometric errors of about 100 seconds per day
Solution Approach 1:
The patent applies local quality by introducing ribs at specific locations along the flexible strip - particularly at the crossing zone and at distances of L/4 to L/2 from the pivot point. These localized structural modifications control anticlastic curvature only where needed, maintaining simplicity elsewhere while achieving chronometric precision without requiring complex overall structural changes.
Solution Approach 2:
The patent employs asymmetry by positioning ribs at unequal distances from the pivot point on either side of the flexible strip. The ribs are located at distances between L/4 and L/2 from the pivot, creating an asymmetric distribution that compensates for the non-linear bending behavior caused by anticlastic curvature, thereby improving isochronism while maintaining manufacturing simplicity.
2Reliability
If multiple flexible strips are combined in parallel to improve guiding function, then guiding capability is enhanced, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The patent enhances guiding capability through local quality by adding ribs at specific critical locations rather than increasing the number of flexible strips. The ribs are positioned at the crossing zone and at distances L/4 to L/2 from the pivot point, providing localized structural reinforcement that improves guiding stability without requiring multiple parallel strips, thus avoiding increased device complexity.
3Reliability
If the height of flexible strips is increased to improve guiding, then guiding function is enhanced, but anticlastic curvature becomes more significant, worsening non-linearity and chronometric precision
Solution Approach 1:
The patent resolves this contradiction by applying local quality - adding ribs at specific locations (crossing zone and L/4 to L/2 from pivot) rather than uniformly increasing strip height. This localized reinforcement controls anticlastic curvature only where it most affects chronometric precision, allowing the strip to maintain adequate height for guiding function while preventing excessive non-linearity through targeted structural modifications.
Solution Approach 2:
The patent uses asymmetry in rib positioning to counteract the increased anticlastic curvature effects that result from taller strips. By placing ribs at asymmetric distances from the pivot point within the L/4 to L/2 range, the structure compensates for the non-linear bending behavior, maintaining isochronism even with increased strip height for improved guiding function.
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 solution achieves good isochronism, extended angular stroke, and simplified manufacturing by controlling anticlastic curvature, reducing errors and enhancing guiding capabilities in mechanical watches.
Implementation Method 1
During a first approximation, if a substantially flat strip is subjected to a moment, it deforms according to an arc of circle
Implementation Method 2
The bent strip has a slight anticlastic curvature. The anticlastic curvature is due to the fact that the fibres outside the neutral surface of the bending strip, must stretch and therefore, also contract in the directions orthogonal to the neutral surface
Data Source
AI summary
A timepiece resonator including an inertial element moveable in relation to a fixed structure, and suspended to a flexible guide including flexible strips crossed in projection on a plane XY at a single crossing zone ZC, each one deformable in a plane parallel to the plane XY each one extending in a ribbon on either side of a neutral surface perpendicular to the plane XY and joining the first recess with the structure and the second recess with the inertial element, and including at least one rib asymmetrical in relation to its neutral surface, and, at the crossing zone ZC, either each flexible strip does not include any rib, or each rib is asymmetrical in relation to its neutral surface.