Chronograph Reset Lever with Rolling Guide Ring
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Solution Overview
Problem
Existing devices for simultaneously resetting two time counters in chronograph mechanisms face challenges due to high frictional forces, which can render the user's action inoperative and prevent precise zero positioning of the counters.
Innovation Solution
A device with a lever having two hammers, where the guide pin with a ring rolls against the edges of a shaped opening to reduce friction, and additional rings are used for guiding and pivoting to accommodate slight offsets and ensure perpendicular force application on the cams, thereby minimizing resistance and ensuring accurate zero positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lever is allowed to pivot slightly to accommodate tolerance offsets, then the counters can be brought to zero position, but friction forces increase and may render user action inoperative
Solution Approach 1:
A ring is introduced as an intermediary element between the guide pin and the shaped opening. The ring rolls against the edges of the opening, mediating the interaction and converting sliding friction into rolling friction, thereby reducing the harmful friction forces while allowing the necessary pivoting motion for precise zero positioning
Solution Approach 2:
The ring introduced on the guide pin provides a curved rolling surface that interacts with the edges of the shaped opening. This curvature transforms the sliding contact into a rolling contact, reducing friction forces while maintaining the degree of freedom needed for precise counter resetting
2Adaptability or versatility
If the lever pivots to accommodate core offsets, then simultaneous reset is achieved, but reaction forces increase and user action becomes inoperative
Solution Approach 1:
The ring acts as a mediator between the guide pin and the shaped opening, reducing the reaction forces generated during pivoting. By converting sliding friction to rolling friction, the ring allows the lever to accommodate core offsets while keeping reaction forces within manageable levels that do not render user action inoperative
3Device complexity
If the guide pin moves directly against the shaped opening edges, then the structure is simple, but friction forces are high and prevent effective user action
Solution Approach 1:
The ring is introduced as a simple intermediary element on the guide pin that significantly reduces frictional resistance. This additional component, while increasing complexity minimally, transforms the high-friction sliding contact into a low-friction rolling contact, enabling effective user action
Solution Approach 2:
The ring provides a curved rolling surface that reduces frictional resistance between the guide pin and the shaped opening edges. This curvature-based solution transforms sliding friction into rolling friction, dramatically reducing the frictional resistance while maintaining structural simplicity
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
The solution significantly reduces frictional forces, allowing for precise and controlled resetting of the counters, ensuring the user's action is effective and the counters are immobilized in the correct zero position, preventing uncontrollable immobilization.
Implementation Method 1
said pin will roll via its ring against these edges and will therefore oppose a lesser frictional force
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A device for a timepiece for the simultaneous resetting of two time counters, particularly for a chronograph mechanism, each of these two time counters being pivoted about an axis fixed to a cam (6b, 8b), the simultaneous resetting device (1) comprising a lever (4) with two hammers (6, 8) which are applied against the respective cams (6b, 8b) when resetting the two time counters, at least one pin (10, 12) serving to guide the lever (4) with two hammers (6, 8) being fixed to this lever (4) and moving in a shaped opening (24, 26) formed in a bridge (28), characterized in that a ring (16a; 16b, 16c) is mounted to rotate freely around the pin (10, 12) and is interposed between said pin (10, 12) and the opening of shape (24, 26) in which it moves.