Watch Crown Locking Structure with Segmented Stem Pipe
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Solution Overview
Problem
Existing watch designs with threadedly locking structures face issues of deteriorated waterproofness and inability to replace parts around the crown due to wear and tear, leading to the need for replacing the entire watch assembly when the threadedly locking function fails.
Innovation Solution
A watch design featuring a barrel with a pipe installation hole and a threaded hole, a stem pipe with an engaging recessed portion and external thread, annular waterproof packing, and a mounting screw that allows for the stem pipe to be securely held and easily removed, maintaining waterproofness and enabling part replacement without affecting the threadedly locking function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stem pipe is brazed to the barrel, then waterproofness is achieved, but parts around the crown cannot be replaced when threadedly locking function deteriorates
Solution Approach 1:
The stem pipe assembly is segmented into separable components: the stem pipe can be independently removed from the barrel by unscrewing the mounting screw. This segmentation allows the stem pipe to be replaced without replacing the entire barrel or watch outer assembly, resolving the contradiction between maintaining waterproofness and enabling part replacement.
Solution Approach 2:
The mounting screw acts as an intermediary element that connects the stem pipe to the barrel while allowing for controlled assembly and disassembly. This intermediary fastening mechanism enables the stem pipe to be securely mounted for waterproofness while also being easily removable for replacement when needed.
2Ease of repair
If the stem pipe is threaded into the barrel, then part replacement becomes possible, but rotation of the stem pipe loosens the threaded engagement and compromises waterproofness
Solution Approach 1:
The mounting system is segmented into two independent functions: the mounting screw provides secure, non-rotating fastening for waterproofness, while the threaded engagement between crown and stem pipe allows for controlled disassembly for replacement. This segmentation prevents rotation of the stem pipe during normal operation while enabling easy removal when needed.
Solution Approach 2:
The mounting screw serves as an intermediary that prevents rotation of the stem pipe relative to the barrel during crown manipulation. By providing a rigid, non-rotating connection, it protects the waterproof packing from loosening while still allowing the entire assembly to be removed for replacement by unscrewing the mounting screw.
3Reliability
If adhesive is used to bond the stem pipe to the barrel, then waterproofness is maintained, but the stem pipe cannot be removed for part replacement
Solution Approach 1:
The connection system is segmented into a removable mechanical fastening (mounting screw) rather than a permanent chemical bond (adhesive). This allows the stem pipe to be securely mounted for waterproofness while remaining independently replaceable by simply unscrewing the mounting screw, avoiding the need for adhesive removal processes.
Solution Approach 2:
The patent replaces the chemical bonding mechanism (adhesive) with a mechanical fastening system (mounting screw). This substitution maintains the waterproofness function while enabling easy mechanical removal and replacement of the stem pipe without the need to break chemical bonds or use specialized removal tools.
Data Source
AI summary
A watch has a crown threadedly locked to a stem pipe mounted to a barrel. The barrel has a pipe installation hole and a threaded hole that extends perpendicular to and in communication with the pipe installation hole. The stem pipe has an insertion portion and a barrel outside protruding portion. The insertion portion is inserted in the pipe installation hole such that the insertion portion can be withdrawn from outside the barrel. The barrel outside protruding portion is disposed outside the barrel and has an external thread to which the crown is removably threaded. An engaging recessed portion is formed in the outer surface of the insertion portion. An annular waterproof packing is sandwiched between the pipe installation hole and the insertion portion. A mounting screw is threaded into the threaded hole so as to be removable back and forth. A front-end portion of the mounting screw is inserted in the engaging recessed portion to hold the stem pipe to the barrel.