Two-Layer Sealing Fastener to Prevent Seal Twisting Damage

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Solution Overview

Problem

Existing screwing fasteners with resin-based ring-shaped members face issues such as peeling, rupturing, and deformation of the seal due to excessive friction, leading to defective fastening and damage, especially when high axial forces are required.

Innovation Solution

A screwing fastener with a two-layer function adding member, comprising a sliding portion and a seal portion, which allows for sliding at the interface to prevent excessive twisting and maintain sealing functionality, while ensuring suitable fastening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a threaded fastener is used to join two components, then the components are securely connected, but the threaded fastener may come into contact with food substances and cause contamination

Engineering Contradiction:

Improveconnection reliabilityVSAvoidfood contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The threaded fastener is divided into two separate parts: a fastening portion that provides the threading and securing function, and a function addition member that acts as a protective barrier. This segmentation allows each part to perform its specific function independently - the fastening portion maintains connection reliability while the function addition member prevents food contamination by creating a barrier between the fastener and food substances.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The function addition member serves as an intermediary element positioned between the threaded fastener and the food substances. This intermediary component prevents direct contact between the fastener and food, thereby eliminating contamination risks while preserving the fastening function. The function addition member mediates the interaction between the fastener and the food environment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the threaded fastener is made of food-safe material, then contamination is prevented, but the fastener may lack sufficient strength or corrosion resistance

Engineering Contradiction:

Improvefood contaminationVSAvoidfastener strength

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The fastening system is segmented into two functional components with different material requirements. The fastening portion can be made from high-strength materials optimized for mechanical performance and corrosion resistance, while the function addition member is made from food-safe materials that provide the protective barrier function. This segmentation allows each component to be optimized for its specific requirements without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The threaded fastener system achieves multi-functionality by combining two components: one optimized for mechanical strength and corrosion resistance, and another optimized for food safety. Together, they provide both structural integrity and contamination prevention, making the overall system universally applicable in food processing environments where both strength and food safety are required.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If a protective coating is applied to the threaded fastener, then food contamination is prevented, but the coating may compromise the threading or corrosion resistance

Engineering Contradiction:

Improvefood contaminationVSAvoidthreading precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

Rather than coating the entire fastener including the threading portions, the protective function is segmented into a separate function addition member. This member is designed to fit over or alongside the fastening portion without interfering with the threading geometry. The segmentation ensures that the precise threading features remain exposed and functional while the function addition member provides the protective barrier against food contamination.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protective function is extracted from the fastening portion and placed into a separate function addition member. This extraction allows the fastening portion to maintain its original threading precision and corrosion-resistant properties without any coating interference, while the function addition member independently provides the food safety barrier. The protective function is separated from the structural function.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP4350180B1Threaded fastener, and function addition member of threaded fastener

Publication Date: 2026.04.29 TOPURA CO LTD

Figure 1(A)~1(D)
Figure 2(A)~2(B)
Figure 3(A)~3(E)

AI summary

To provide a screwing fastener that is capable of preventing damage to a function adding member when tightening, and is capable of maintaining suitable functions of the function adding member and a suitable fastened state. A screwing fastener includes a fastener main body 10, a screw portion 13 for tightening the fastener main body 10 to a fastened member 200, a flange portion 14 provided to the fastener main body 10, and a seal function adding member 20 (function adding member) that is provided to the flange portion 14, in which the seal function adding member 20 comes into contact with the fastened member when tightening. The seal function adding member 20 has at least a two-layer structure of a sliding portion 22 (first adding portion) that is in contact with the flange portion 14, and a seal portion 21 (second adding portion) that comes into contact with the fastened member 200.