Watch Barrel One-Piece Sub-Assembly Design
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Solution Overview
Problem
Existing watch barrels face challenges in achieving a high power reserve while maintaining rigidity and minimizing component count and machining costs, particularly in reducing the bung diameter without compromising material strength and risk of breakage.
Innovation Solution
A watch barrel design featuring a one-piece sub-assembly coaxial with the shaft and ratchet, where the ratchet is integrated with the shaft and core, allowing for a reduced bung diameter with improved rigidity and power reserve, and utilizing a multiphase alloy spring with a specific width-to-thickness ratio, and a Teflon coating to reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the bung diameter is reduced to increase power reserve, then the space available for the spring increases, but the risk of breakage increases due to insufficient material section
Solution Approach 1:
The patent merges the shaft and ratchet into a single integrated component (one-piece sub-assembly), which consolidates the structural load-bearing functions and eliminates the need for separate fastening elements that would require additional material sections, thereby reducing the bung diameter while maintaining reliability
Solution Approach 2:
The patent specifies the use of titanium alloy for the one-piece sub-assembly, which provides high strength-to-weight ratio and fatigue resistance, allowing the reduced diameter shaft to maintain sufficient material section for reliability while enabling the power reserve increase
2Duration of action of moving object
If the shaft diameter is reduced to allow greater power reserve, then more space is available for the spring, but the rigidity of the ratchet drive decreases
Solution Approach 1:
By integrating the ratchet directly onto the shaft as a one-piece sub-assembly, the patent creates a rigid monolithic structure that eliminates potential weak points at connection interfaces, maintaining drive rigidity despite the reduced overall diameter
Solution Approach 2:
The titanium alloy material provides high specific stiffness, enabling the reduced diameter shaft to maintain sufficient rigidity for the ratchet drive while still allowing the increased power reserve
3Reliability
If traditional ratchet mounting with screw and square is used, then the ratchet is securely fixed, but the minimum pivot bearing diameter increases
Solution Approach 1:
The patent integrates the ratchet as an integral part of the shaft through direct forming or forging of the one-piece sub-assembly, eliminating the need for separate fixation elements like screws and squares, thereby reducing the pivot bearing diameter while maintaining secure fixation
Solution Approach 2:
The patent removes the separate fixation components (screw, square) from the traditional assembly, extracting only the essential function of securing the ratchet to the shaft through the integrated one-piece construction
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 design enhances power reserve and rigidity while maintaining economical machining costs and reducing the risk of breakage, with a flexible spring material selection and optimized spring attachment.
Implementation Method 1
a Teflon coating to reduce friction
Data Source
Figure 1~3
AI summary
A watch barrel (1) for pivoting between a plate (9) and a bridge (5) and comprising at least one spring (7) housed between a pivoting drum (6) and a ratchet (2) and attached between, at its outer end, said drum (6) and at its inner end, a shaft (3) which is pivotally fixed to said ratchet (2) about a pivot axis (D). Said barrel (1) comprises a one-piece sub-assembly (10) coaxial with said shaft (3) and grouping, around a core (4), said shaft (3) and said ratchet (2) which is located in the immediate vicinity of said plate (9).