Chronograph Coupling Lever Ovalized Cap Adjustment Mechanism

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Solution Overview

Problem

Existing chronograph mechanisms face challenges in achieving precise adjustment of the penetration of the intermediate wheel's toothing into the chronograph wheel due to manufacturing tolerances and roundness issues, requiring complex and manual eccentric adjustments.

Innovation Solution

A device featuring an ovalized cap on the column wheel that adjusts the penetration of the intermediate wheel's teeth into the chronograph wheel, eliminating the need for an eccentric by using an oval peripheral surface to precisely control the clutch rocker's movement, allowing for easier and more precise adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an eccentric is used to adjust the stroke of the clutch rocker, then the penetration of the toothing can be adjusted, but the mechanism becomes more complex and requires manual operation with a hewer

Engineering Contradiction:
Improveadjustment precisionVSAvoidmechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the eccentric component from the adjustment mechanism. Instead of using an eccentric to adjust the clutch rocker stroke, the patent uses a direct adjustment method where the clutch rocker's pivot position is modified, thereby simplifying the mechanism while maintaining adjustment precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using an eccentric (rotating offset component) to achieve adjustment, the invention inverts the approach by directly positioning the clutch rocker pivot relative to the column wheel, achieving the same functional result through a reversed mechanical arrangement

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If an eccentric is used for adjustment, then the penetration can be controlled, but the installation requires manual operation with a hewer

Engineering Contradiction:
Improvepenetration control precisionVSAvoidinstallation ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention removes the eccentric component that necessitates manual hewer operation. The adjustment is achieved by repositioning the clutch rocker pivot directly, which can be done with standard tools and procedures, greatly improving installation ease

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adjustment mechanism is designed to be self-adjusting through the relative positioning of the clutch rocker and column wheel, eliminating the need for specialized manual intervention with hewers during installation

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If manufacturing tolerances and roundness issues are considered, then precise penetration adjustment becomes difficult, but adding adjustment mechanisms increases complexity

Engineering Contradiction:
Improvetoothing penetration precisionVSAvoidadjustment device complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention performs preliminary action by pre-positioning the clutch rocker pivot at the correct location relative to the column wheel before final assembly. This preliminary positioning ensures that even with manufacturing tolerances in the toothing, the penetration is correctly established from the outset

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the critical parameter from the eccentric offset to the clutch rocker pivot position. By adjusting this position, the penetration of the toothing is controlled, compensating for manufacturing tolerances in the wheel toothing without requiring complex adjustment devices

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1947531B1Device for adjusting the amplitude of movement of the coupling lever of a chronograph with column wheel
Publication Date: 2015.08.19 PATEK PHILIPPE SA
  • EP1947531B1 patent drawingFigure 1
  • EP1947531B1 patent drawingFigure 2
  • EP1947531B1 patent drawingFigure 3

AI summary

The device has a curved support face (16) carried by a tip (14) of a coupling lever (10) and co-operating with a cam (6) partially located above a crown wheel (1). The tip has a terminal portion (18) co-operating with an oval shaped peripheral surface (17) of crowns (2) of the crown wheel. An angular position of the cam determines penetration of gear teeth of an intermediate wheel (13) in gear teeth of a chronograph wheel (15). A screw fixes the cam in a desired angular position.