Ceramic Watch Strap Permanent Pin Assembly

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Solution Overview

Problem

Ceramic watch straps with high strength and smooth surfaces face issues with pin abrasion and temporary securing of fastening pins, leading to potential disassembly and increased manufacturing costs due to the need for screw fastening structures at fixed nodes.

Innovation Solution

A ceramic watch strap design featuring outer and central connecting pieces made of ceramic materials, with stainless steel connecting and fastening pins that utilize press-fitting and latching mechanisms to secure pins permanently, eliminating the need for screw fastening and allowing for easy assembly and high fastening force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ceramic material is used for watch strap to achieve high strength and smooth surface, then appearance and durability are improved, but pin abrasion occurs and permanent securing of fastening pins becomes difficult

Engineering Contradiction:
Improvestrength of ceramic materialVSAvoidpermanent securing of fastening pins
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The fastening pin is divided into two functional parts: a head portion for press-fitting into the ceramic outer connecting piece and a shaft portion for engagement with the connecting pin. This segmentation allows each part to perform its specific function optimally while preventing abrasion of the ceramic material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting pin acts as an intermediary element between the ceramic outer connecting pieces and the ceramic central connecting piece. It provides a metal surface that can be permanently engaged with the fastening pin shaft, preventing direct contact and abrasion between ceramic components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If screw fastening structure is used at fixed nodes to secure pins, then fastening force is improved, but manufacturing time increases and component costs increase

Engineering Contradiction:
Improvefastening forceVSAvoidmanufacturing time
Core Design Contradiction:
ForceVSProductivity

Solution Approach 1:

The screw fastening mechanism is extracted and replaced with a press-fitting mechanism. The fastening pin head is pressed directly into the ceramic outer connecting piece through the insertion groove, eliminating the need for screws and screw holes, thereby reducing manufacturing steps and costs while maintaining fastening force.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ceramic outer connecting piece itself provides the fastening function through its insertion groove and latching step structure. The fastening pin is press-fitted directly into the ceramic material, allowing the ceramic component to serve both structural and fastening functions, eliminating the need for separate fastening hardware.

Inventive Principle:
Principle #25Self-service

3Reliability

If screw fastening structure is used at fixed nodes, then fastening reliability is improved, but manufacturing costs increase due to additional components and assembly steps

Engineering Contradiction:
Improvefastening reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fastening function is merged with the ceramic outer connecting piece structure. The insertion groove and latching step are integrated into the ceramic component itself, combining the structural support and fastening functions into a single component, thereby reducing part count and assembly complexity while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fastening pin is designed as a simple, inexpensive component with a head portion for press-fitting and a shaft portion for engagement. This simple design reduces manufacturing cost compared to screw fastening systems while providing sufficient reliability for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The design provides a durable, aesthetically pleasing ceramic watch strap with a permanent securing structure that prevents disassembly and reduces manufacturing costs by eliminating the need for screw fastening, ensuring long-term reliability and ease of production.

Implementation Method 1

the fastening pin is press-fitted into the fastening hole of the connecting pin through the insertion groove of the outer connecting piece

Methodology Applied
Scientific EffectPress-fitting: Mechanical Force

Implementation Method 2

the fastening pin is press-fitted into the fastening hole of the connecting pin through the insertion groove of the outer connecting piece and supported on the connecting pin by the latching step

Methodology Applied
Scientific EffectLatching mechanism: Mechanical Force

Data Source

PatentEP2382890B1Watch strap having permanent assembly structure based on characteristics of ceramics
Publication Date: 2015.07.29 CERAART CO LTD
  • EP2382890B1 patent drawingFigure 1
  • EP2382890B1 patent drawingFigure 2
  • EP2382890B1 patent drawingFigure 3

AI summary

The present invention relates to a watch strap, which is made of a special material such as ceramics to have high strength and a smooth surface and includes a permanent assembly structure allowing easy securing of fastening pins (140) through press-fitting of the fastening pins while providing high fastening force. The watch strap includes outer connecting pieces (110), each including a pair of pin grooves (111) formed at one side thereof and a pair of insertion grooves (112) formed at a back side thereof to communicate with the corresponding pin grooves, a central connecting piece (120) having a pair of pin holes (121) penetrating the central connecting piece to correspond to the pin grooves of the outer connecting pieces, connecting pins (130) each including a fastening part (131a) having fastening holes (132a) formed at opposite ends of the fastening part, and a fastening pin having a latching step (144) formed at one end of the fastening pin. The fastening part of each of the connecting pins is inserted into the pin groove of the outer connecting piece through the pin hole of the central connecting piece, and the fastening pin is press-fitted into the fastening hole of the connecting pin through the insertion groove of the outer connecting piece and supported on the connecting pin by the latching step.