Watch Movement Pinion with Self-Locking Pins
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Solution Overview
Problem
Conventional watch movement drive mechanisms for date rings lack sufficient shock resistance and require bulky, costly positioning jumpers, and existing solutions like the Geneva mechanism are complex and prone to jamming.
Innovation Solution
A pinion with diametrically opposed pins forming a self-locking system that penetrates alternately into the toothing of the date ring, providing a dead angle for shock resistance and eliminating the need for a positioning jumper by ensuring correct positioning and shockproofing during rotation in dead angular zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positioning jumper with high elastic constant is used to ensure date ring positioning and shock resistance, then shock resistance is improved, but the torque required to overcome the jumper increases and the device complexity increases
Solution Approach 1:
The invention extracts and eliminates the positioning jumper from the date display mechanism by redesigning the pinion-tooth interaction. The pinion is configured with specific geometric features (circular arc profile, dead angle) that enable inherent positioning and shock resistance without requiring an additional jumper component.
Solution Approach 2:
The pinion is designed to perform multiple functions: driving the date ring, positioning it accurately, and providing shock resistance. The dead angle configuration allows the pinion to automatically engage and lock into tooth hollows during rotation, enabling self-positioning and self-locking without external positioning mechanisms.
2Adaptability or versatility
If a Geneva mechanism is used to drive multiple indicators with a single motor, then the motor can perform multiple functions, but the device complexity increases and jamming risk increases
Solution Approach 1:
The pinion is designed as a universal driving element that can drive multiple different indicators (date ring, day window, month window) with a single motor. The dead angle configuration allows the same pinion to periodically engage with different toothing structures, enabling one motor to control multiple display functions without complex switching mechanisms.
3Device complexity
If pins with small diameter are used in the pinion, then the dead angle is maintained, but the pins become fragile and prone to damage during shocks
Solution Approach 1:
The pinion pins are designed with non-uniform geometry: small diameter at the engagement end to maintain dead angle and fit into tooth hollows, and larger diameter at the base for structural strength. This gradient design allows the pin to be fragile only where necessary for function while remaining strong overall to withstand shock loads.
Data Source
Figure 1~2
Figure 3~4B
Figure 5~6
AI summary
The watch movement (44) is equipped with an analog display device for information whose value varies periodically or intermittently, this analog display device comprising an indicator (4B) of said information provided with teeth (5B) and a mechanism for periodically or intermittently driving this indicator, this mechanism comprising a rotating mobile whose pinion, in meshing relationship with the teeth, is formed of two pins (46) which are diametrically opposed relative to the axis of rotation (A10) of the rotating mobile, these two pins being configured to penetrate alternately into successive hollows (7B) of the teeth and to form a self-locking system in case of shocks suffered by the watch movement.Each of the two pins has, in a general plane of the teeth perpendicular to the axis of rotation of the rotating mobile, a transverse profile of which a first outer part (38) is substantially in the form of an arc of a circle centered on the axis of rotation.