Chronograph Zeroing Device Single-Operation Reset Mechanism
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Solution Overview
Problem
Prior zeroing devices for chronographs often require multiple operations of the reset pushbutton to fully reset the center minute hand and second hand to zero, and excessive force can damage the linkage.
Innovation Solution
A zeroing device comprising a first zeroing unit with a zeroing lever and latch, and a second zeroing unit arranged above the first, which converts the rotational movement of a control cam into a directed pushing motion to ensure both hands are reset to zero with a single operation of the reset pushbutton, using a pendulum rod, hinge support, and joint rod to apply force to heart-shaped cams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional zeroing device is used, then the structure is simple, but multiple operations of the reset pushbutton are required to fully reset the hands to zero
Solution Approach 1:
The zeroing device is divided into two independent zeroing units: a first zeroing unit with a zeroing lever and latch that engages with a heart-shaped minute zeroing cam, and a second zeroing unit with similar components that engages with a heart-shaped second zeroing cam. This segmentation allows each unit to independently control one hand's resetting, enabling both hands to be reset simultaneously with a single pushbutton operation while maintaining manageable structural complexity
Solution Approach 2:
Both zeroing units are integrated into a single mechanism driven by one reset pushbutton. The pushbutton simultaneously actuates both the first and second zeroing units through shared linkage, merging the control of two separate zeroing functions into one unified operation, thus achieving full reset of both hands with a single action
2Force
If excessive force is applied to reset the hands, then the resetting action is stronger, but the linkage may be damaged
Solution Approach 1:
The heart-shaped cams are designed with controlled engagement surfaces that naturally limit the force transmitted during resetting. The cam profiles ensure that the zeroing levers engage smoothly without shock loads, and the latch mechanisms are positioned to engage at optimal points in the cam rotation, preventing excessive force from being applied to the linkage while still achieving reliable resetting
Solution Approach 2:
The heart-shaped cams act as intermediaries between the reset pushbutton and the zeroing levers. They convert the linear motion of the pushbutton into controlled rotational motion, mediating the force transmission to ensure smooth, shock-free engagement of the zeroing mechanism, thereby protecting the linkage from damage while maintaining effective resetting force
3Productivity
If a single pushbutton operation is used to reset both hands, then the operation is faster, but the mechanism becomes more complex
Solution Approach 1:
The reset pushbutton serves multiple functions simultaneously: it actuates both zeroing units, controls both heart-shaped cams, and resets both hands in one operation. This multi-functionality achieves rapid resetting (improved productivity) while the modular design of two independent but coordinated units keeps the overall complexity manageable through functional integration
Data Source
AI summary
A zeroing device (200), including a first zeroing unit (71), which consists of a zeroing lever (12) having a zeroing lever arm (12a) and a zeroing lever latch (12b), wherein the zeroing lever latch (12b) has a first end (13) and a second end (14).The zeroing device is characterized by a second zeroing unit (72) that is arranged at an offset to the first zeroing unit (71) in a Z coordinate direction (Z) and is in operative connection with the first zeroing unit (71). The second zeroing unit (72) may also include a pendulum rod (31), a hinge support (34), and a joint rod (35), wherein the pendulum rod (31) is rotatably attached to a cam (33) and to the joint rod (35) and wherein the joint rod (35) is rotatably attached to the hinge support (34) and rests against an eccentric (36) of the zeroing lever (12).