Oscillating Mass Shock Absorber Plate for Micro-Rotor Watch
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Solution Overview
Problem
In micro-rotor watch movements, the reduction in oscillating mass radius leads to a loss of inertia, necessitating increased thickness, which eliminates the elastic mass support, making the suspension susceptible to shock damage, and existing shock absorption methods are inadequate.
Innovation Solution
A shock absorber in the form of a plate, fixed at one end to the oscillating mass and the other end to a rotating tube, absorbs shocks, preventing stress on the suspension and protecting it from damage, while abutment means like grooves and retaining tabs limit axial movement to prevent contact with the case or plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the radius of the oscillating mass is reduced to form a micro-rotor, then the thickness of the timepiece is reduced, but the moment of inertia is reduced requiring increased thickness which eliminates the elastic mass support
Solution Approach 1:
The oscillating mass is segmented into two functional parts: a rigid heavy sector providing inertia and a flexible support structure providing shock absorption. This segmentation allows the mass to simultaneously achieve compact dimensions and shock resistance by separating the inertia-generating function from the shock-absorbing function.
Solution Approach 2:
The oscillating mass combines a rigid heavy sector (made of dense material for inertia) with a flexible support structure (made of elastic material for shock absorption). This composite construction allows the system to achieve both compact size and shock resistance by using materials with complementary properties in different functional zones.
2Force
If axial play of the rotor on its shaft is increased to compensate for shock, then the shock is absorbed, but the face of the rotor may contact the back of the timepiece causing damage
Solution Approach 1:
The flexible support structure preemptively absorbs shock forces through elastic deformation before they can transmit to the shaft suspension or cause the rotor face to contact the timepiece back. This preliminary action prevents the harmful contact by counteracting the shock force through the elastic arms' deformation.
Solution Approach 2:
The flexible support structure acts as an intermediary between the oscillating mass and the shaft suspension, absorbing shock forces through its elastic deformation rather than allowing direct transmission to the suspension or contact between the rotor face and timepiece back.
3Reliability
If the mass support is made flexible to absorb shocks, then shock protection is improved, but the structural strength is reduced
Solution Approach 1:
Different parts of the oscillating mass structure have different mechanical properties: the heavy sector is made rigid and strong for maintaining inertia, while the support arms are made flexible for shock absorption. This local differentiation of material properties allows each part to optimize its function without compromising the other.
Solution Approach 2:
The mass support is segmented into rigid connection zones (for structural strength) and flexible deformation zones (for shock absorption). This segmentation allows the structure to simultaneously achieve high strength where needed and flexibility where required for shock protection.
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 shock absorber effectively distributes shock stress, preserving the suspension integrity and preventing damage, while ensuring the decorated face does not contact the case, maintaining the watch's structural integrity and aesthetics.
Implementation Method 1
the axial shocks undergone by the mass are absorbed by the elasticity of these arms
Implementation Method 2
A shock absorber in the form of a plate, fixed at one end to the oscillating mass and the other end to a rotating tube, absorbs shocks
Data Source
Figure 1~4
Figure 5~6
Figure 7~9
AI summary
The weight (2) has a shock absorber in the form of a plate, where one end of the plate is secured to the oscillating weight, and the other end of the plate is fixed to a tube arranged to rotate about an arbor forming an axis of rotation of the oscillating weight. A stop unit is implemented to limit the axial shake of the oscillating weight in the event of any shock, where the stop unit includes a groove, which is penetrated by a retaining tongue that forms an end of a banking bridge.