Offset Stem Watch Mechanism for Crown Recentering
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Solution Overview
Problem
Existing time-setting mechanisms for watches with offset stems often result in an off-center winding crown, leading to aesthetic issues and operational inefficiencies due to friction and complexity, particularly in recentering and disassembly processes.
Innovation Solution
A time-setting mechanism with a main stem carrying a sliding pinion and an auxiliary stem integral with the control crown, where the pull tab's connecting element links the auxiliary rod to cause axial translation, allowing easy pivoting and extraction of the rods without additional components, thus simplifying construction and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a time-setting system with offset stems is used to recenter the winding crown, then the aesthetic appearance is improved, but the mechanism complexity increases due to additional components like riders and connecting pieces
Solution Approach 1:
The patent combines the time-setting function and the crown recentering function into a single integrated mechanism. The pull rod, when actuated, simultaneously transmits motion to both the sliding pinion for time-setting and the auxiliary stem for recentering the winding crown, eliminating the need for separate riders and connecting pieces
Solution Approach 2:
The auxiliary stem serves multiple functions: it acts as a structural support element, a motion transmission element for recentering the crown, and a component that works in conjunction with the sliding pinion for time-setting. This multi-functionality reduces the overall number of components needed in the system
2Shape
If traditional offset stem mechanisms are used, then the winding crown can be recentered, but friction and risk of buttressing increase during operation
Solution Approach 1:
The patent extracts the problematic rider component from the mechanism and replaces it with a direct connection between the pull rod and the auxiliary stem. This eliminates the sources of friction and buttressing that were inherent in the rider-based translation mechanisms of prior art
Solution Approach 2:
The auxiliary stem acts as an intermediary element that translates the pull rod's motion into crown recentering action without requiring direct contact between the pull rod and the crown assembly. This intermediary role reduces friction and improves operational reliability
3Shape
If additional non-standard elements are introduced to achieve offset stem functionality, then the winding crown can be recentered, but the manufacturing complexity and size increase significantly
Solution Approach 1:
The patent segments the time-setting mechanism into distinct functional modules: the main stem with sliding pinion for time-setting, and the auxiliary stem with pull rod for recentering. This segmentation allows each component to be manufactured separately using standard processes and then assembled, reducing overall manufacturing complexity
Solution Approach 2:
Instead of modifying the main stem to achieve offset functionality, the patent introduces a separate auxiliary stem that performs the recentering function. This inversion of the problem-solving approach allows both stems to remain relatively simple in design while achieving the desired offset effect
4Ease of operation
If the stem carrying the winding crown is made integral with multiple components, then the time-setting function is achieved, but the extraction of the stem becomes difficult during disassembly
Solution Approach 1:
The patent designs the auxiliary stem as a separate, extractable component that is connected to the main stem through a defined interface. This segmentation allows the auxiliary stem to be removed independently during disassembly or repair without requiring disassembly of the entire time-setting mechanism
Solution Approach 2:
The patent incorporates a pull rod that can be actuated to preliminary disengage the auxiliary stem from its engaged position before complete removal. This preliminary action facilitates easier extraction of the stem during maintenance operations
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 mechanism effectively recenters the control crown, reduces friction and bulk, and facilitates easy extraction of the rods, enhancing the operational simplicity and aesthetic harmony of the watch.
Implementation Method 1
a pull rod pivotally mounted on a pivot axis and arranged to cause movement of said sliding pinion during pivoting of said pull rod on its pivot axis
Implementation Method 2
the pull tab comprises a connecting element cooperating with the auxiliary rod and arranged to link said auxiliary rod to the pull tab so that a movement in axial translation of the auxiliary rod causes the pull tab to pivot on its axis of swivel
Data Source
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AI summary
The present invention proposes a time-setting mechanism for a timepiece comprising a time-setting system with offset rods having a main rod (4) carrying a sliding pinion (6) arranged to perform at least the time setting and an auxiliary rod (8) integral with a control crown (3), arranged to control at least the time setting, said main rod (4) and auxiliary rod (8) having respective axes parallel to each other and not coincident, and being arranged to be connected at least in rotation to each other, as well as a pull-rod (12) pivotally mounted on a pivot axis (A) and arranged to cause a displacement of said sliding pinion (6) when said pull-rod (12) is pivoted on its pivot axis (A),characterized in that the pull tab (12) comprises a connecting element (18) cooperating with the auxiliary rod (8) and arranged to link said auxiliary rod (8) to the pull tab (12) such that an axial translational displacement of the auxiliary rod (8) causes the pull tab (12) to pivot about its pivot axis (A).