Bidirectional Date Correction Mechanism for Timepiece

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Solution Overview

Problem

Conventional date mechanisms in timepieces face difficulties in bidirectional correction due to abrupt cam profiles, preventing reverse date indication adjustments as the control arm locks against the steep flank, making it impossible to correct the date in the reverse direction.

Innovation Solution

A bidirectional corrector mechanism featuring a control rocker with a rake, actuated by a cam, and a return rocker with a rake, controlled by a disengagement member via a control rod, allowing the control rocker to be momentarily moved away from the cam's path, enabling both forward and reverse corrections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a cam with an abrupt flank is used to mark the transition from the last day to the first day, then the date indicator can advance forward automatically, but the control arm locks against the steep flank when attempting reverse correction

Engineering Contradiction:

Improveforward date correctionVSAvoidbidirectional correction capability

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The correction mechanism is segmented into distinct functional components: a control rocker for forward correction, a return rocker for reverse correction, and a disengagement member that separates the two correction paths. This segmentation allows each component to specialize in one direction of correction without interference from the other, resolving the locking issue that prevented bidirectional operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The disengagement member acts as an intermediary that selectively engages or disengages the control rocker from the cam profile. During reverse correction, it disengages the control rocker to prevent locking against the abrupt flank, while during forward correction, it allows normal engagement. This intermediary mechanism enables bidirectional correction by mediating the interaction between the control arm and cam

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the control arm follows the cam profile for automatic date advancement, then forward date correction works smoothly, but reverse correction becomes impossible due to locking on the steep flank

Engineering Contradiction:

Improveautomatic date advancementVSAvoidreverse date correction

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The mechanism dynamically switches between two operational modes: normal mode where the control rocker follows the cam profile for automatic advancement and forward correction, and correction mode where the disengagement member activates the return rocker to enable reverse correction. This dynamic switching allows the system to maintain reliability of automatic advancement while adding reverse correction capability when needed

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

For reverse correction, the mechanism inverts the normal operation by using the return rocker to push the date indicator backward against the cam profile, rather than allowing the control arm to follow the profile forward as in normal operation. This inverted approach enables reverse correction by applying force in the opposite direction through the disengagement member

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP1918792B1Timepiece including a correction mechanism for a device displaying a time quantity

Publication Date: 2010.04.21 CO DES MONTRES LONGINES FRANCILLON SA

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Figure 3A

AI summary

The timepiece has a two-directional corrector mechanism provided for a display device, which displays a time related quantity e.g. date. The display device is actuated by a control lever (14), where the lever is controlled by a cam on which the control lever abuts. A correction device e.g. annular cam, is actuated by a control stem (42) in a display device correction phase. The correction device moves the control lever out of a path of the cam. The control lever normally abuts in a normal operating phase of the timepiece.