Removable Shape Memory Alloy Deckring for Watch Crown Seal Maintenance
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Solution Overview
Problem
Existing watch crowns with non-removable deckrings complicate seal replacement and increase manufacturing costs due to the difficulty in handling and machining small, intricate components, often requiring costly replacement of the entire crown when sealing properties deteriorate.
Innovation Solution
A watch crown with a removable deckring made of shape memory material, such as Nitinol, that can be deformed for assembly and disassembly without damaging other parts, allowing for easy replacement of seals without compromising sealing properties, using gripping zones on the crown or deckring for facilitated handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-removable deckring is used to maintain sealing properties, then the sealing reliability is improved, but the ease of repair deteriorates because seal replacement requires replacing the entire crown
Solution Approach 1:
The deckring is separated from the crown body, transforming it from a fixed integrated component to a removable independent part. This segmentation allows the deckring to be detached and reattached, enabling seal replacement without replacing the entire crown while maintaining sealing reliability through the reusable deckring structure.
Solution Approach 2:
The deckring is designed to be temporarily removed during seal replacement and then recovered/reattached to restore sealing. This allows the valuable crown structure to be preserved while only the consumable seal is replaced, improving repair economics and accessibility.
2Ease of manufacture
If a traditional crimped ring is used to secure the seal, then the manufacturing process is simple, but the ease of operation deteriorates because seal replacement is not possible
Solution Approach 1:
The deckring transitions from a static permanently crimped state to a dynamic removable and reattachable state. This allows the structure to adapt between assembly mode (where the deckring is installed) and maintenance mode (where it can be removed for seal access), resolving the contradiction between manufacturing simplicity and repair accessibility.
3Ease of operation
If a circlip is used to retain the seal, then the ease of operation is improved for assembly and disassembly, but the device complexity increases due to the need for grooves and beaks
Solution Approach 1:
The complex circlip retention mechanism (with grooves and beaks) is extracted and replaced by a simpler deckring structure that achieves the same retention function through a different approach. The deckring uses a straightforward overlying structure with gripping zones rather than intricate groove-beak geometries, reducing overall device complexity while maintaining ease of operation.
4Volume of moving object
If the deckring is made small to fit the crown, then the compactness is improved, but the ease of operation deteriorates because handling becomes difficult
Solution Approach 1:
The deckring incorporates asymmetric gripping zones with protrusions or notches that provide mechanical advantage for handling. These asymmetric features create natural hand engagement points that leverage human finger mechanics, allowing small components to be easily manipulated despite their compact size necessary for crown fitment.
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
Enables efficient and cost-effective replacement of worn seals without structural modifications to the crown, maintaining equivalent sealing and axial holding properties, and simplifying the assembly and disassembly process.
Implementation Method 1
A watch crown with a removable deckring made of shape memory material, such as Nitinol, that can be deformed for assembly and disassembly without damaging other parts
Data Source
AI summary
The crown (1) has a cap (11) formed by integrating a cover (112) with a lateral skirt. A removable deck ring (60) made of shape memory alloy material covers toroid cross-section diameter of an O-ring joint, and is arranged on a shoulder (1161) arranged at a bottom face of the cap. A space is formed between an inner circumference of the removable deck ring and an outer circumference of a central pipe (2) of the crown, where space size is less than or equal to 1.5 times of the toroid cross-section diameter. Two gripping areas (1162) are formed on the deck ring on the crown. An independent claim is also included for a method for assembling and disassembling a removable deck ring of a timepiece crown.