Watch Mechanism Disengaging Wheel Set for Over-Tension Prevention
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Solution Overview
Problem
Hand-wound watches face the challenge of over-tensioning the barrel spring during winding, which can lead to damage, reduced power reserve, and lack of tactile feedback for optimal winding.
Innovation Solution
A watch mechanism featuring a disengaging wheel set in the kinematic chain from the winding pinion to the barrel arbor, which disengages when the torque exceeds a predetermined threshold, preventing over-tension and allowing tactile feedback for optimal winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sliding flange is used to prevent over-tension, then the risk of breakage is reduced, but the power reserve is reduced by one barrel revolution
Solution Approach 1:
The patent introduces a disengaging wheel set as an intermediary mechanism between the winding pinion and barrel arbor. This wheel set includes a wheel mounted to rotate freely around the barrel arbor and a pawl or jumper that engages with the wheel's teeth. The disengaging wheel set acts as a mediator that allows the winding mechanism to function normally while preventing over-tension through the disengagement feature, without requiring a sliding flange that would consume barrel revolution space.
Solution Approach 2:
The winding mechanism is segmented into distinct functional components: the winding pinion, the disengaging wheel set (with wheel, pawl/jumper, and spring), and the barrel arbor. This segmentation allows the disengaging wheel set to independently handle the over-tension prevention function without interfering with the primary winding function, enabling full power reserve utilization while maintaining reliability.
2Reliability
If a sliding flange is used to prevent over-tension, then breakage is avoided, but tactile feedback for optimal winding is lost
Solution Approach 1:
The disengaging wheel set serves as an intermediary that transmits tactile feedback from the winding mechanism to the user. As the barrel spring approaches optimal winding, the increased tension causes the pawl or jumper to interact with the wheel's teeth, creating audible clicks and tactile resistance that inform the user of the winding status, unlike a sliding flange that operates silently and smoothly.
Solution Approach 2:
The mechanism incorporates inherent feedback through the interaction between the pawl/jumper and the wheel's teeth. When the barrel spring reaches optimal tension, the force required to continue winding increases, causing the pawl or jumper to disengage and re-engage with the teeth, producing audible clicks and tactile sensations that provide real-time feedback to the user about the winding status.
3Reliability
If a sliding flange is used to prevent over-tension, then over-winding is avoided, but debris accumulation and malfunctions increase
Solution Approach 1:
The disengaging wheel set introduces an intermediary mechanical interface between the winding pinion and barrel arbor. This interface uses discrete components (wheel with teeth, pawl or jumper, spring) that maintain better clearance and reduce the risk of debris accumulation compared to the sliding flange's continuous contact surface. The toothed engagement provides natural clearance zones that prevent debris buildup.
Solution Approach 2:
The disengaging wheel set employs dynamic engagement through the spring-loaded pawl or jumper that can flex and disengage as needed. This dynamic mechanism maintains optimal contact pressure and clearance throughout operation, preventing debris accumulation that would occur with the static sliding flange design. The spring ensures consistent engagement force while allowing for minor misalignments and debris ejection.
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 prevents over-tensioning of the barrel spring, avoiding potential damage, maintaining power reserve, and providing tactile feedback for optimal winding, enhancing user experience and watch reliability.
Implementation Method 1
at least one pawl or jumper (91, 92) mounted on said wheel and spring-loaded to engage with the teeth of the star
Data Source
Figure 1~3
Figure 4~6
AI summary
The invention relates to a watch mechanism (10) comprising a winding mechanism and a barrel, wherein the kinematic chain extending from the winding pinion (15) of the winding mechanism to the shaft (13) or the drum (12) of the barrel includes a disengagement mechanism, said disengagement mechanism being designed so that it is capable of disengaging when the torque generated by the barrel spring exceeds a certain value. The invention also relates to a timepiece comprising such a mechanism.