Clock Barrel Plug Segmentation for Reduced Bung Diameter
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Solution Overview
Problem
Conventional barrel architectures face limitations in reducing the bung diameter due to physical constraints, which hinders the reduction of the barrel arbor diameter and associated components, making it difficult to increase the power reserve by reducing the bung radius to spring thickness ratio below 10, while ensuring structural integrity and ease of disassembly for mainspring exchange.
Innovation Solution
A barrel assembly with a reduced bung diameter is designed, featuring a plug with a decreasing outer diameter from a collar to a second end, incorporating multiple coaxial parts for improved structural support and extraction means, allowing axial extraction of the plug, and a ratchet fixation system that ensures contact in both pivoting and axial directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the bung diameter is reduced to increase power reserve, then the space available for the spring increases, but the structural integrity and fatigue strength become insufficient
Solution Approach 1:
The plug is divided into multiple coaxial parts (first part with pivot bearings, second part with receiving surface, third part with collar) that can be assembled together. This segmentation allows each part to be optimized for its specific function while maintaining overall structural integrity, enabling the plug to achieve sufficient strength with a reduced overall diameter.
Solution Approach 2:
The multiple coaxial parts of the plug are nested together along the pivot axis, with each part fitting within or alongside the others. This nested arrangement maximizes the use of available space while maintaining the required structural strength, allowing the plug to support the necessary loads with a reduced diameter compared to conventional single-piece designs.
2Volume of moving object
If the bung diameter is reduced below conventional dimensions, then the power reserve increases, but the ease of disassembly for mainspring exchange deteriorates
Solution Approach 1:
The plug is segmented into multiple coaxial parts that can be disassembled and reassembled. This segmentation enables the mainspring to be exchanged by removing and reassembling the plug components, maintaining ease of repair despite the reduced overall diameter that would otherwise make disassembly difficult.
3Volume of moving object
If the ratio of bung radius to spring thickness is reduced below 10, then the power reserve increases, but the risk of breakage increases
Solution Approach 1:
By segmenting the plug into multiple optimized coaxial parts, each part can be designed with appropriate material sections and thicknesses to maintain sufficient strength and reliability, even when the overall plug diameter is reduced to achieve a ratio below 10 with the spring thickness.
Data Source
Figure 1~2
Figure 3~5
Figure 6~11
AI summary
The barrel assembly (1) has a main spring (2) mounted between a drum (3) and a receiving surface (5) having a core (4) coaxial to the drum about an axis (D). The core includes a fixing unit (120) for fixing a ratchet and/or a pivot bearing in a plate, a bearing (43) for pivoting the drum, and a collar (40) projecting from the bearing on an inner surface (31) of the drum toward the spring. Another bearing (44) radially set back from the receiving surface pivots a cover (7) for closing the assembly, and another pivot bearing (182) is provided in a plate or a bridge of a clock mechanism. An independent claim is also included for a timepiece movement.