Ceramic Watchstrap Links With Buffer Pins
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Solution Overview
Problem
Bracelets made with low impact resistance materials like ceramics and sintered hard metals are prone to brittle fracture and breakage under mechanical shock, especially at the articulation pins, rendering them unusable and costly to repair.
Innovation Solution
Incorporating a clearance or groove at the open ends of holes in the links to prevent direct contact between the linking members and the links, reducing stress concentrations and allowing for a more even distribution of mechanical loads through a grooved pin design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ceramic or sintered hard metal links are used in the bracelet, then durability and aesthetic value are improved, but impact resistance deteriorates due to brittle fracture
Solution Approach 1:
A metal buffer element is introduced as an intermediary component between the ceramic link and the articulation pin. This buffer element absorbs and distributes impact forces, preventing direct transmission of shock loads to the brittle ceramic material while allowing the ceramic to maintain its durability and aesthetic functions.
Solution Approach 2:
The bracelet link assembly becomes a composite structure combining ceramic material (for durability and aesthetics) with metal buffer elements (for shock absorption). This composite approach allows each material to contribute its advantageous properties while mitigating the weaknesses of individual materials.
2Device complexity
If ceramic links with pin holes are used, then the bracelet structure is simplified, but stress concentration at hole edges causes systematic breakage at articulation pins
Solution Approach 1:
The metal buffer element serves as a mediator between the pin and the ceramic link's hole edge. It redistributes the contact stresses from the pin over a larger area of the buffer element, preventing stress concentration at the hole edges and eliminating the systematic breakage problem while maintaining structural simplicity.
Solution Approach 2:
The stress distribution parameter is changed by introducing the buffer element, which transforms the concentrated stress field at the hole edge into a distributed stress field across the buffer element's contact surface, thereby preventing brittle fracture.
Data Source
AI summary
The invention relates to a watchstrap (1) including a plurality of mutually hinged elements (7) which each comprise at least one link (2, 3, 4, 4′) and at least one recess consisting of at least one hole (15, 15′) for receiving therein a linking member (10, 11, 12). Next to the open ends (16) of at least some of said holes (15, 15′), a clearance (20) of the linking member (10, 11, 12) is provided, preventing any contact at said point between the latter and said links (2, 3, 4, 4′).