Split-Seconds Chronograph Rocker Reset for Precise Counter Zeroing
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Solution Overview
Problem
Existing chronograph mechanisms with fraction-of-a-second counters face complexity, increased parts, imbalance issues, and imprecision in resetting due to rapid rotation, and existing solutions are either too complex or imprecise.
Innovation Solution
A chronograph mechanism with a rocker mechanism that includes a chronograph gear driven by a secondary energy source, featuring a reset mechanism with a movable rocker that angularly positions the counter wheel for precise resetting, using a differential clutch and a lightning bolt rocker to manage rapid rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional hammer is used to strike a reset cam on the fraction-second counter, then the reset function is achieved, but the mechanism complexity increases and the number of parts increases
Solution Approach 1:
The single hammer is designed to perform multiple functions: it strikes the reset cam of the fraction-second counter and also strikes the reset cam of the seconds counter, eliminating the need for a separate hammer for each counter and reducing overall mechanism complexity
Solution Approach 2:
The reset cams of different counters are positioned such that they can be struck by a single hammer action, combining multiple reset operations into one mechanical action and reducing the number of parts required
2Reliability
If a reset cam is added to the fraction-second counter, then the reset function is provided, but imbalance problems occur during rapid rotation
Solution Approach 1:
The reset cam is extracted from the rotating fraction-second counter and repositioned on the stationary plate, allowing the counter to rotate freely without the imbalance caused by a rotating reset cam, while still enabling the reset function through the hammer striking the cam on the plate
3Device complexity
If a clutch mechanism is used to connect the escape wheel to the lightning seconds pinion axis, then the reset function is achieved without a reset cam, but the manufacturing complexity increases and precision is reduced
Solution Approach 1:
The system uses the existing rotational motion of the escape wheel and the mechanical connection through the hammer and reset cam to achieve the reset function, eliminating the need for complex clutch mechanisms and achieving precise positioning through the inherent precision of the escape wheel rotation and cam geometry
Data Source
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AI summary
One aspect of the invention relates to a clockwork movement (1) comprising a timekeeping gear train (100) driven by a first energy source (150) and regulated by a regulating member (120); a chronograph mechanism (10) comprising a chronograph gear train (20) driven by a second energy source (35) comprising a chronograph counter (23) having a counter wheel (231); a chronograph start/stop control device (30) configured to couple the chronograph gear train (20) to the regulating member (120) on demand; a reset mechanism (40) for resetting said chronograph counter (23) comprising a reset control (60) movable between a neutral rest position and a reset position;the chronograph mechanism (10) comprising a rocker (70) configured to be driven by the chronograph start/stop control device (30) between a first stable position in which the rocker (70) blocks the rotation of the counter wheel (231) and a second stable position in which the counter wheel (231) is free to rotate; the reset control (60) being configured to cooperate with the rocker (70) to angularly position it in a third intermediate position in which the rocker (70) allows the counter wheel (231) to rotate until it is positioned in a reset reference position under the effect of the second energy source driving the chronograph gear train.