Digital Watch Gear Train Friction Reduction
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Solution Overview
Problem
Digital watches require strong stepping forces to advance number disks cyclically, which increases frictional forces, especially when advancing the hours number disk, making it difficult to minimize the force required for disk adjustments.
Innovation Solution
A compact gear train design that advances the drive wheel in cyclical steps, using a unit wheel to rotate the unit number disk at 10 steps per revolution, a stepping device to advance the tens number disk at 6 steps per revolution, and a mechanism to advance the hours number disk at 12 steps per revolution, with rotational blocking devices to minimize friction and allow for low-force adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a digital display with number disks is implemented in a small wristwatch, then the watch size is reduced, but the frictional forces required to advance the number disks increase
Solution Approach 1:
The number display is segmented into separate number disks for units, tens, and hours, each capable of independent rotation. This segmentation allows the drive mechanism to advance disks sequentially with minimal friction at any given moment, rather than requiring simultaneous advancement of all disks
Solution Approach 2:
The patent implements a dynamic blocking mechanism where blocking devices prevent number disks from rotating except during designated adjustment periods. This dynamic control eliminates continuous friction resistance, allowing the watch to maintain compact size while reducing the force required for disk advancement
2Force
If rotational blocking devices are added to minimize friction during disk advancement, then the force required for adjustment is reduced, but the device complexity increases
Solution Approach 1:
The blocking devices are merged with the existing number disk structure, where the blocking elevations are integrated into the disk periphery and the blocking devices are combined with the drive train components. This merging approach adds rotational blocking functionality without significantly increasing overall device complexity
Solution Approach 2:
The blocking devices serve multiple functions: they prevent unwanted rotation of number disks during normal operation, enable controlled advancement during adjustment periods, and maintain positional accuracy. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity
Data Source
AI summary
A watch with a drive by which a gear train of a digital display having one or more number disks driven in rotation in cyclical steps and a manually actuatable disk adjusting mechanism. A drive wheel is advanced rotationally in steps by the drive of the watch and rotationally blocked between the steps. A unit wheel of a unit number disk can be rotationally advanced at ten steps per revolution. A stepping device, driven by the unit wheel drives a tens number disk rotationally at six steps per revolution. An hours number disk, is rotationally advanced directly or indirectly by the tens number disk at twelve steps per revolution during one revolution of the tens number disk.