Watch Movement Flange with Variable Rigidity for Impact Resistance
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Solution Overview
Problem
Existing watch movement fixation systems in watch cases are prone to plasticization and loss of contact during assembly and impacts, leading to potential dismantling issues due to inadequate stress distribution and material deformation.
Innovation Solution
The use of elastic casing flanges with modifiable rigidity, featuring specific geometries and materials like superelastic alloys, to maintain contact and resist deformation under stress, ensuring a robust and reliable fixation system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid flanges are used for fixing the movement, then the movement is securely held in place, but the flanges are prone to plastic deformation during assembly and under impact
Solution Approach 1:
The flange is designed with variable rigidity along its length, with different sections having different elastic moduli or geometric properties. The support surface is positioned to create a longer effective lever arm for the holding function while maintaining a shorter, stiffer section for impact resistance. This parameter variation allows the flange to provide strong holding force without undergoing plastic deformation during assembly or impact events.
Solution Approach 2:
The flange is segmented into functionally distinct zones: a support surface region that contacts the caseband, a transition zone with varying thickness or material properties, and a fixing region that contacts the movement. This segmentation allows each zone to be optimized for its specific function - the support surface provides leverage for secure mounting while the transition zone absorbs stress to prevent plastic deformation.
2Reliability
If the flange is made more rigid to prevent deformation, then impact resistance improves, but the risk of plasticization during assembly increases
Solution Approach 1:
The flange incorporates a gradient in rigidity parameters along its length, with the section contacting the caseband having higher rigidity for impact resistance, while the section engaging the movement allows for greater elasticity during assembly. This parameter gradient enables the flange to resist impact forces without transmitting excessive stress to the movement during assembly, reducing sensitivity to manufacturing tolerances.
3Strength
If the flange geometry is optimized for secure mounting, then the movement is firmly fixed, but the system becomes more sensitive to manufacturing and assembly tolerances
Solution Approach 1:
The flange is designed with dynamic geometric features such as curved contact surfaces or compliant sections that can adapt to variations in manufacturing tolerances. The support surface is shaped to provide a mechanical advantage that maintains fixation strength while accommodating tolerance variations through elastic deformation or geometric adaptation, reducing the system's sensitivity to precision requirements.
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 solution provides a durable fixation system that minimizes plastic deformation and untimely dismantling, maintaining contact and stability during impacts, and is less sensitive to manufacturing and assembly tolerances, enhancing the overall reliability and robustness of the watch movement attachment.
Implementation Method 1
The flange 1 is thus elastically deformed during assembly of the movement so that the elastic restoring force of the flange holds a surface 2b* of the movement 2* against a surface 3b* of the caseband 3*
Implementation Method 2
The at least one flange 1 is made of a superelastic alloy and/or a shape memory alloy, in particular a nickel-titanium alloy such as Nitinol
Implementation Method 3
The at least one flange 1 is made of a superelastic alloy and/or a shape memory alloy
Data Source
Figure 1~2
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AI summary
System (10) for fixing a watch movement (2) to a watch case element (30), the system comprising: - at least one flange (1), in particular at least two flanges, preferably three or four flanges, intended to come into contact with the movement on the one hand and with the watch case element on the other hand, and - a device (2a'; 3a') for modifying the rigidity of at least one flange, in particular for modifying the bending rigidity of at least one flange, when the movement is fixed and/or moved relative to the watch case element.