Natural Escapement Safety Teeth for Controlled Escape-Wheel Motion
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Solution Overview
Problem
Existing natural escapements in clockwork movements are prone to premature triggering, leading to mechanical damage and loss of timekeeping function due to uncontrolled rotation of escape wheels when the balance wheel rotates slowly or during manipulation, especially at low amplitude or end of barrel spring autonomy.
Innovation Solution
A natural escapement design with safety teeth on the balance wheel that engage with escapement wheels before the impulse pallets, preventing uncontrolled rotation by retaining the wheels when they are not retained by the escapement function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the natural escapement is designed without safety teeth, then the escapement operates freely with direct tangential impulse to the balance wheel, but the escape wheels can rotate uncontrolled when the balance wheel rotates slowly or during manipulation, causing premature triggering and mechanical damage
Solution Approach 1:
The safety teeth are positioned to engage with the escape wheel teeth before the impulse pallets engage, preventing uncontrolled rotation in advance. This preliminary engagement ensures that the escape wheels are held back before the impulse phase begins, eliminating premature triggering and mechanical damage risks
2Reliability
If safety teeth are added to the balance wheel, then uncontrolled rotation is prevented and operational safety is improved, but the complexity of the escapement structure increases
Solution Approach 1:
The balance wheel is given multiple functions: it performs its primary oscillation function while also carrying safety teeth that engage with the escape wheel teeth to prevent uncontrolled rotation. This multi-functionality allows the balance wheel to serve both timekeeping and safety functions simultaneously
3Reliability
If the escape wheels are held back by the escapement function, then controlled operation is maintained, but when the balance wheel rotates too slowly with small amplitude, the impulse pallets may not reach the rotational range of the teeth, causing the escape wheels to escape control
Solution Approach 1:
The safety teeth provide a preliminary restraining action on the escape wheels that is independent of the impulse pallet engagement. This preliminary anti-action ensures that even when the balance wheel rotates slowly and the impulse pallets fail to engage properly, the escape wheels remain controlled by the safety teeth engagement
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
The invention relates to a natural escapement (1) for a clockwork movement carrying out a succession of operating cycles, each composed of a first and a second alternation of a balance wheel (16) which includes a balance wheel (18) on an axle (20) of which is fitted a balance plate (22), this natural escapement (1) comprising a first escapement mobile having at least one first set of teeth (10), this first escapement mobile, arranged to be driven by a mobile of the clockwork movement's gear train, in turn driving a second escapement mobile having at least one second set of teeth (38), the first and second escapement mobiles forming a kinematic chain arranged to cooperate with an anchor (30) adapted to pivot around an anchor rod (32),The balance wheel (22) carrying a second impulse pallet (28) by which this balance wheel (22) receives a direct and tangential driving impulse from the first escape wheel during the first oscillation, and a first impulse pallet (26) by which this balance wheel (22) receives a direct and tangential driving impulse from the second escape wheel (12) during the second oscillation, the balance wheel (22) also carrying at least one first safety tooth (52) arranged to cooperate with the teeth (10, 38) of one of the first and second escape wheels so as to lock this first or second escape wheel when it escapes from the second impulse pallet (28), respectively from the first impulse pallet (26). The invention also relates to a clock movement comprising such a natural escapement (1).