Watch Dial Fastening via Segmented Core and Preliminary Assembly
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Solution Overview
Problem
Existing watch case designs face challenges in securely attaching the dial and movement without damaging the dial, require complex and precise manufacturing, and have issues with water resistance and maintenance accessibility due to complex constructions and material aging.
Innovation Solution
A watch design featuring a separate fastening means that secures the dial relative to the housing using a screw connection, allowing independent fixation of the dial before the housing cover is connected, with options for bayonet or snap-in connections for easy assembly and maintenance, and a pressure transmission means to distribute pressure evenly and prevent dial damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the core is screwed into the watch case to reinforce the case and support the movement, then the case structure is strengthened, but the internal structure becomes expensive to manufacture and the dial alignment becomes difficult to adjust
Solution Approach 1:
The invention divides the case into two separate parts: the case body and the core. The core is designed as a detachable component that can be independently manufactured and assembled. This segmentation allows each part to be optimized separately for strength and manufacturing simplicity, reducing overall complexity while maintaining structural integrity.
Solution Approach 2:
The dial is pre-aligned and fixed to the case body before the core is screwed into place. This preliminary action ensures that the dial alignment is established independently of the core assembly process, eliminating the need for complex alignment adjustments after core installation.
2Ease of operation
If the movement is detachably connected to the core after assembly, then the movement can be attached, but pre-assembly is not possible and additional tools are required
Solution Approach 1:
The movement is pre-assembled and aligned with the dial on a separate work carrier before the core is installed. This preliminary assembly allows all movement components to be positioned and secured in advance, simplifying the final installation process when the core is screwed into the case.
Solution Approach 2:
A work carrier is introduced as an intermediary component that temporarily holds the movement and dial assembly during the assembly process. This work carrier facilitates easy attachment and detachment of the movement without requiring complex tooling or procedures.
3Reliability
If the core is screwed in a precisely predetermined direction to waterproof the crown tube, then water resistance is achieved, but the assembly process becomes more complex
Solution Approach 1:
The crown tube is designed with a conical shape that creates a self-aligning sealing surface. When the core is screwed in, the conical geometry automatically guides the crown tube into the correct angular position, ensuring waterproof sealing without requiring precise predetermined screwing directions or complex alignment procedures.
4Reliability
If the rear case cover is screwed to the core to ensure water resistance, then sealing is improved, but if the core loosens, the case cover also lifts out and exposes the watch to water ingress
Solution Approach 1:
The sealing function is merged into the interface between the case cover and case body, rather than relying solely on the connection between the case cover and core. Multiple sealing elements are positioned at different locations to create redundant sealing paths, ensuring that water resistance is maintained even if one connection point loosens.
Solution Approach 2:
Multiple sealing elements are installed in advance at different locations within the case assembly. These pre-positioned seals provide a buffer against potential loosening of the core or case cover, ensuring that water ingress is prevented even if one sealing path is compromised.
5Strength
If movement retaining rings are used to clamp the movement, then the movement is secured, but the construction becomes complex and requires high precision manufacturing
Solution Approach 1:
The movement retaining function is merged into the core structure itself. The core is designed with integrated features that directly secure the movement, eliminating the need for separate retaining rings and reducing the number of components required.
Solution Approach 2:
The core is designed to perform multiple functions: it reinforces the case structure, supports the movement, provides alignment references, and incorporates sealing surfaces. This multi-functionality reduces the need for additional specialized components like separate retaining rings.
6Ease of operation
If elastic rings are used to secure the construction, then the assembly is fixed, but the construction may loosen due to shrinkage from aging
Solution Approach 1:
Metal sealing elements with elastic deformation capability are used instead of pure elastic rings. These metal seals can elastically deform during assembly to accommodate tolerances but are resistant to permanent deformation and shrinkage from aging, providing long-term stability.
Solution Approach 2:
The sealing system uses composite construction combining metal components with elastic deformation properties. This composite approach provides both the initial fixation capability needed for assembly and the long-term dimensional stability required to prevent loosening over time.
Data Source
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AI summary
The clock (1) has a housing (2) that comprises an interior space (20) in which a dial plate (4) and a clock unit (3) are arranged. The clock unit is connected with the dial plate, and the interior space is closed by a housing cover (27). The dial plate lies in a system position at the housing. A fastening unit (24) stays in engagement with the housing and separately formed at the housing cover. The fastening unit fixes the dial plate opposite to the housing in the system position and is rotated from a detached position into an attached position.