Natural Escapement Safety Levers for Balance-Absence Locking
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Solution Overview
Problem
Existing natural escapements in horological movements are prone to premature release of the escapement impulse in the absence of the balance, leading to uncontrollable rotation of escape wheels, which can cause loss of timekeeping function, undesired advance, or sudden stop, and potential component deterioration.
Innovation Solution
A natural escapement with first and second safety levers on the anchor's arms to ensure locking of escape wheels in the absence of the balance, preventing uncontrollable rotation by pivoting the anchor to engage the escape wheels with stop pallet-stones during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the natural escapement is designed without safety levers to maintain simplicity and ease of operation, then the ease of operation is improved, but the reliability deteriorates due to premature release of escapement impulse in the absence of the balance
Solution Approach 1:
The safety levers are pre-positioned on the anchor arms to automatically engage with the escape wheels when the balance is absent, preventing premature impulse release before the balance is installed. This preliminary positioning ensures the escapement cannot operate without the balance, eliminating the reliability issue while maintaining design simplicity.
Solution Approach 2:
The safety levers act as intermediary elements between the anchor and the escape wheels, providing a mechanical intervention that prevents direct engagement between the escape wheels and impulse pallet-stones when the balance is absent. This intermediary mechanism resolves the contradiction by adding a simple protective element that enhances reliability without significantly complicating the overall escapement design.
2Reliability
If safety levers are added to prevent premature release of escapement impulse, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The safety function is segmented into separate lever elements mounted on the anchor arms, rather than attempting to integrate the safety mechanism into the existing anchor structure. This segmentation allows the safety levers to be added as simple, independent components that perform a single function (preventing escape wheel rotation) without interfering with the complex impulse transmission mechanism, thus minimizing the increase in overall device complexity.
Solution Approach 2:
Instead of designing the escapement to be inherently safe and then adding complexity to maintain safety, the invention inverts the approach by designing the safety mechanism first (the levers that block escape wheel rotation) and then building the functional escapement around it. This inversion allows the safety feature to be implemented as a simple prerequisite condition rather than a complex active control system.
3Loss of energy
If the escape wheel is made free to rotate for natural escapement operation, then the efficiency is improved by direct tangential impulse transfer, but the stability deteriorates causing incorrect positioning and operational safety issues
Solution Approach 1:
The safety levers provide preliminary anti-action by preventing the escape wheels from rotating in the absence of the balance, countering the instability that would otherwise occur. This preliminary blocking action ensures that the free-rotating escape wheels only become operational when properly constrained by the balance through the anchor, thus maintaining both the efficiency benefits of free rotation and the stability needed for correct positioning.
Data Source
AI summary
A natural escapement for horological movement including a balance that moves from a first extreme position to a second extreme position and vice versa by passing through a middle locking position, this balance including a balance wheel on an arbor of which is adjusted a balance plate, the natural escapement also including a first escape wheel set driven by a wheel set of the train of the horological movement and driving in turn a second escape wheel set, the first and second escape wheel sets forming a kinematic chain cooperating with an anchor, the balance plate carrying a second impulse pallet-stone which receives a driving impulse from the first escape wheel set during the first alternation, and a first impulse pallet-stone which receives a driving impulse from the second escape wheel set during the second alternation.