Nonlinear Intermediate Spring for Constant-Elastic Moment
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Solution Overview
Problem
Constant force devices in watch mechanisms, such as those using spiral or sinuous elastic arms, deliver a force to the escapement that varies significantly between windings, affecting the regularity of oscillator oscillations due to varying elastic return moments with winding angle.
Innovation Solution
A watch mechanism employing an intermediate spring with a non-linear elastic return moment curve, featuring a plateau over a specific range of winding angles, ensuring a substantially constant force delivery to the escapement, achieved through the use of specially shaped elastic arms and optimized geometric design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional intermediate springs (spiral, sinuous elastic arms, or rectilinear elastic arms) are used in constant force devices, then the device can transmit energy to the escape wheel, but the elastic return moment varies significantly with the winding angle, causing the force delivered to the escapement to decrease between successive windings
Solution Approach 1:
The patent applies parameter changes by designing the intermediate spring with a non-linear elastic return moment curve that features a plateau region. Specifically, the spring is engineered so that between winding angles θa and θb (separated by at least 10°), the elastic return moment remains substantially constant (varying by no more than 10%). The spring is pre-loaded with an angle θarm within this plateau range, ensuring that during operation, the winding angle remains within [θa, θb], thereby maintaining constant force delivery to the escapement and improving oscillator regularity.
2Stability of the object's composition
If a very high winding frequency is chosen to reduce the variation in elastic return moment, then the force variation decreases, but the duration between successive windings becomes very short, reducing the overall energy transmission efficiency
Solution Approach 1:
The patent resolves this contradiction by changing the fundamental parameter of the spring's elastic return moment characteristic from linear to non-linear with a plateau. This allows the system to maintain constant force delivery (improving regularity) while operating at moderate winding frequencies, as the constant force region provides a wide angular range (at least 10°) over which the spring can deliver consistent energy without requiring frequent re-winding.
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 maintains a consistent force delivery to the escapement, improving the regularity of oscillator oscillations by maintaining a constant elastic return moment within a defined angular range, thereby enhancing the timekeeping accuracy of the watch mechanism.
Implementation Method 1
the intermediate spring is a spring with non-linear behavior which produces, between a winding angle θa and a winding angle θb separated by at least 10°, an elastic return moment which does not vary by more than 10%
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The watch mechanism (1) according to the invention comprises a drive element (2), an oscillator (5), an escapement (4) for maintaining the oscillations of the oscillator (5), an intermediate spring (19) for supplying mechanical energy to the escapement (4), one or more gears (2a, 3, 10) between the drive element (2) and the intermediate spring (19), and a locking device (20) allowing periodic winding of the intermediate spring (19) by the drive element (2) via the gear(s) (2a, 3, 10). The intermediate spring (19) is a nonlinear spring that produces, between a winding angle θa and a winding angle θb separated by at least 10°, an elastic restoring moment that does not vary by more than 10%. The intermediate spring (19) is pre-wound with a value θarm included in the range [θa, θb]. The clock mechanism (1) is further arranged so that, during its operation, the winding angle of the intermediate spring (19) remains in the range [θa, θb].