Pointer Timepiece High-Speed Date Change Mechanism
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Solution Overview
Problem
Pointer type timepieces, such as wristwatches, experience a delay of about three to four hours in changing the display of date and day of the week due to the ratchet wheel's one revolution in 24 hours, leading to mid-display deviations.
Innovation Solution
A pointer type timepiece design incorporating a high-speed rotating wheel that meshes with the ratchet wheel's teeth, allowing the ratchet wheel to rotate at high speed and transmit this speed to the display wheel through a feed wheel, enabling quick display changes while maintaining normal pointer movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ratchet wheel rotates at normal speed (one revolution in 24 hours), then the pointer moves normally, but the display change takes three to four hours causing mid-display deviation
Solution Approach 1:
The system dynamically switches between two rotation modes: normal speed mode for pointer movement and high speed mode for display change. The high speed rotating wheel engages with the ratchet wheel's teeth only during display change, enabling rapid rotation without affecting normal pointer operation. This dynamic mode switching resolves the contradiction by allowing fast display updates when needed while maintaining normal operation otherwise.
Solution Approach 2:
The rotation function is segmented into two independent paths: one through the normal rotating wheel for pointer movement, and another through the high speed rotating wheel for display change. The high speed rotating wheel has teeth that mesh with the ratchet wheel's teeth, creating a separate high speed transmission path. This segmentation allows display change to occur rapidly without interfering with normal pointer operation, eliminating mid-display deviation.
2Productivity
If a high speed rotating wheel is added to enable rapid display change, then display update speed improves, but device complexity increases
Solution Approach 1:
The high speed rotating wheel is merged with the existing ratchet wheel structure by having its teeth mesh with the ratchet wheel's teeth. This integration allows the high speed rotating wheel to utilize the same tooth engagement mechanism as the normal rotating wheel, adding high speed capability without requiring a completely separate transmission system. The merging approach reduces complexity compared to adding entirely independent high speed mechanisms.
Solution Approach 2:
The ratchet wheel serves multiple functions: it acts as a speed reducer for normal operation and as a high speed transmission element when engaged with the high speed rotating wheel's teeth. The feed wheel also serves dual purposes by transmitting motion from the ratchet wheel in both normal and high speed modes. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while achieving high productivity.
Data Source
AI summary
A high-speed rotating wheel rotates at high speed by a third stepper motor which meshes with a portion of teeth of a ratchet wheel. A transmission projection of the ratchet wheel moves within an elongated hole of a transmission wheel which rotates with the movement of the hour hand. The ratchet wheel rotates at high speed, and a display wheel rotates at high speed by the high speed rotation of the ratchet wheel via a feed wheel. When normally moving the hour hand, the ratchet wheel rotates with the transmitting wheel and the portion of teeth of the ratchet wheel is made to approach the high-speed rotating wheel. When the display of the display wheel changes, the high-speed rotating wheel meshes with the portion of teeth of the ratchet wheel and rotates the ratchet wheel at high-speed. Accordingly, the date display of the display wheel can be quickly changed.