Retrograde Timepiece Display Safety Mechanism
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Solution Overview
Problem
Retrograde timepiece display mechanisms, whether using rigid or flexible elements, pose a risk of damage when users attempt to manually correct the time display, as they may force the mechanism during automatic changes, leading to potential breakage.
Innovation Solution
A safety device is integrated into the retrograde timepiece display mechanism that blocks manual correction attempts when the drive finger is engaged with the display wheel, using a combination of elastic components and a cam system to prevent the display wheel from being driven in the opposite direction, thus protecting the mechanism from user-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flexible element such as a flexible finger is used in the kinematic chain to allow bidirectional correction, then the ease of operation is improved, but the reliability deteriorates because the flexible element risks plastic deformation or breaking when forced in the opposite direction
Solution Approach 1:
The safety device applies preliminary anti-action by detecting when the flexible finger is engaged with the display wheel and preventing any manual correction attempts during this period. The device blocks the correction mechanism before the user can apply force in the wrong direction, thus preventing plastic deformation or breaking of the flexible element while maintaining bidirectional correction capability when safe
2Ease of operation
If manual correction is allowed at all times, then the ease of operation is improved, but the object-generated harmful factors worsen because the mechanism risks damage when the drive finger is engaged with the display wheel
Solution Approach 1:
The safety device implements feedback by continuously monitoring the engagement state of the drive finger with the display wheel through the feeler-spindle and cam mechanism. When engagement is detected, the device automatically blocks manual correction; when disengaged, correction is permitted. This feedback loop eliminates mechanism damage risk while maintaining correction availability when safe
3Reliability
If a safety device is added to block manual correction during drive finger engagement, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The safety device uses a feeler-spindle as an intermediary element that detects drive finger engagement and transmits this information to the blocking mechanism. The cam profile acts as another intermediary that converts the feeler-spindle's linear motion into rotational blocking motion. These intermediary elements provide reliable protection through simple geometric relationships rather than complex control systems
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 safety device allows users to manually correct the time display without risking damage to the mechanism, ensuring the display wheel is only moved in the intended direction, thereby preventing deformation or breakage.
Implementation Method 1
a flexible finger consisting of a beak (18) extended by at least one elastic coil (20)
Implementation Method 2
The safety device comprises a fork (78) pivotally mounted about a fourth pivot centre (80) and which is provided with a feeler-spindle (82). This safety device (52) is coupled to the intermediate correction device (66) via an articulation (84) for example of a ball joint type.
Data Source
AI summary
A retrograde timepiece display mechanism for a watch including a wheel for displaying information, this display wheel being driven by a drive finger carried by a wheel driven by a horological movement, in order to change the information displayed by the retrograde timepiece display mechanism from one value to the immediately following value, this retrograde timepiece display mechanism including also an intermediate correction device to manually correct the information provided by the retrograde timepiece display mechanism by acting on a correction finger which drives the display wheel, the retrograde timepiece display mechanism also including a safety device arranged to allow blocking the intermediate correction device by preventing the correction finger from driving the display wheel during a period of time when the change in the information displayed by the retrograde timepiece display mechanism occurs and when the drive finger is engaged with the display wheel.