Timepiece Striking Mechanism With Variable Spring
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Solution Overview
Problem
Conventional striking mechanisms in timepieces face challenges in achieving repeatable striking rates and sound quality due to variations in torque, hammer inertia, and assembly tolerances, leading to sensitivity to orientation and parasitic noise, with existing solutions either lacking adjustability or increasing complexity and wear.
Innovation Solution
A simplified design where the hammer and anchor form a single piece, incorporating a preloaded elastic limiting spring that acts as a shock absorber, allowing adjustable striking frequency and reducing noise and wear by attenuating shocks and rebound effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the hammer mass is increased to maximize inertia and achieve low striking frequency for better sound diffusion, then sound diffusion is improved, but the striking rate becomes more sensitive to gravity and orientation
Solution Approach 1:
The patent introduces a variable spring constant k(θ) that changes with the hammer's angular position θ. The spring is softer when the hammer is horizontal (θ=0) and stiffer when vertical (θ=π/2), compensating for gravitational effects and maintaining consistent striking frequency across different orientations
Solution Approach 2:
The patent transitions from a fixed rigid stop to a dynamic elastic spring element whose stiffness varies with position. This dynamic compliance allows the system to adapt to gravitational variations while maintaining stable oscillation characteristics
2Device complexity
If a rigid stop is used to limit hammer movement, then the mechanism is simple, but it produces parasitic noise and premature wear from repeated impacts
Solution Approach 1:
The elastic spring acts as an intermediary between the hammer and the fixed support, mediating the impact forces. Instead of direct rigid contact, the spring deforms elastically to absorb and dissipate impact energy, eliminating the jarring noise of rigid stops
Solution Approach 2:
The spring provides预先 cushioning by being pre-compressed or pre-tensioned, so that when the hammer impacts, the cushioning effect is already in place. This prevents the sudden rigid impact that causes noise and wear
3Ease of manufacture
If separate anchor and hammer components are used, then the design is conventional, but assembly tolerances increase variability in striking frequency
Solution Approach 1:
The patent merges the anchor and hammer into a single integral component. This eliminates the interface between separate parts, removing the source of tolerance accumulation and ensuring consistent striking frequency across all assembled units
4Manufacturing precision
If the striking mechanism is made adjustable to compensate for tolerance variations, then striking frequency consistency is improved, but device complexity increases
Solution Approach 1:
The patent uses a variable spring constant k(θ) that automatically adjusts the effective stiffness based on the hammer's position. This passive parameter variation compensates for tolerance effects without requiring active adjustment mechanisms
Solution Approach 2:
The spring's variable stiffness特性 automatically compensates for orientation and tolerance variations without external intervention. The system self-regulates its striking frequency based on its own state, eliminating the need for complex adjustment mechanisms
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
This design reduces the dispersion of striking frequency, enhances sound quality and duration by adjusting the striking rate, and minimizes the impact of orientation on the striking dynamics, while reducing parasitic noise and wear.
Implementation Method 1
a limiting element in the form of an elastic spring, the other end of which is fixed to the frame, this limiting spring being pre-loaded, which makes it possible to adjust the striking frequency of the striking hammer
Implementation Method 2
The elastic nature of the limiting spring allows it to return a large part of the energy absorbed during the elastic deformation of the spring by the hammer, and thus affects the hammer's striking rate
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The timepiece has a frame (1) carrying a striking mechanism. The mechanism comprises a motor element (10) kinematically linked with a striking wheel (20) and a striking hammer (40). The mechanism comprises an anchor (30) with pallets (31, 32) engaged alternately with the wheel and cooperating with the hammer to oscillate the hammer between a first striking position and a second striking position of a gong (50). A heel (42) of the hammer is in contact with a limiting spring (60), where the anchor and the hammer form a single striking element mounted to pivot on the frame.