Pipe Coupling Coil Spring Locking Structure Against Deformation

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Solution Overview

Problem

Conventional pipe coupling members with coil springs suffer from plastic deformation and disengagement due to excessive forces from high-speed fluid flow, causing instability in the valve mechanism.

Innovation Solution

A pipe coupling member design featuring a coil spring with a fitting portion, locking portion, expanding-contracting portion, and valve support portion, where the locking portion stabilizes the fitting portion within a spring fitting groove, preventing deformation and disengagement, and maintaining the valve element's position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the coil spring has an enlarged-diameter portion fitted into an annular groove of the coupling body, then the coil spring can be installed without splitting the coupling body or attaching additional members, but the coil spring may be plastically deformed or disengaged from the groove when excessive force acts on it

Engineering Contradiction:
Improvestructure complexityVSAvoidcoil spring stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The coil spring is divided into distinct functional portions: a fitting portion (18a) for installation into the groove, a locking portion (18b) with adjacent turns to prevent disengagement, and an expanding-contracting portion (18c) for valve operation. This segmentation allows each portion to perform its specific function optimally while working together as a unified spring system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the coil spring are given different structural characteristics tailored to their specific functions. The fitting portion has a diameter matching the groove for secure installation, the locking portion has adjacent turns to prevent radial displacement, and the expanding-contracting portion has spaced turns to provide the necessary elastic deformation for valve actuation.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the valve element is pressed by high-speed fluid flow, then the valve element can be forced open, but the coil spring may be displaced considerably and plastically deformed

Engineering Contradiction:
Improvevalve opening capabilityVSAvoidcoil spring resistance to deformation
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The locking portion (18b) with adjacent turns is positioned to engage the fitting portion (18a) before excessive displacement can occur. This preliminary engagement creates a mechanical constraint that prevents the spring from being displaced beyond its elastic limit, even when subjected to high forces from fast-moving fluid.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The locking portion acts as a preventive measure against plastic deformation. By having the adjacent turns engaged and constrained within the groove, the spring is protected in advance from the harmful effects of excessive displacement that would otherwise cause permanent deformation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the enlarged-diameter portion of the coil spring is reduced in diameter to allow insertion, then the coil spring can be installed through the fluid passage, but the enlarged-diameter portion may be pulled inward and disengaged from the groove

Engineering Contradiction:
Improveinstallation easeVSAvoidfitting portion position stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The fitting portion (18a) is designed with a specific diameter that matches the annular groove (26) to ensure proper engagement. During installation, the spring is compressed to reduce its diameter temporarily for insertion, then expands to engage the groove. The locking portion (18b) with adjacent turns provides an additional mechanical constraint that prevents the fitting portion from being pulled inward and disengaged after installation.

Inventive Principle:
Principle #10Preliminary action

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 enhances the structural stability and prevents plastic deformation of the coil spring under high forces, ensuring reliable operation and simplified installation without the need for splitting the coupling body or additional support members.

Implementation Method 1

a coil spring formed by helically winding a wire, the coil spring being disposed between the coupling body and the valve element to urge the valve element toward the closed position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a locking portion contiguous with the fitting portion, the locking portion being formed by winding the wire a plurality of turns such that the turns of wire are adjacent to each other in the direction of the longitudinal axis

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP3441658B1Pipe joint member having valve body, and coil spring used in said pipe joint member
Publication Date: 2023.08.02 NITTO KOHKI CO LTD
  • EP3441658B1 patent drawingFigure 1~3
  • EP3441658B1 patent drawingFigure 4A~4B

AI summary

Provided is a pipe coupling member configured to prevent a coil spring from being plastically deformed or dislodged from a coupling body even when a large force acts on a valve element. A pipe coupling member (10) includes a coupling body (14) having a fluid passage (12), a valve element (16) displaceable in the fluid passage (12), and a coil spring (18) urging the valve element (16) toward a closed position. The coil spring (18) is formed by helically winding a wire and has a fitting portion (18a) fitted and secured in a spring fitting groove (26), a locking portion (18b) contiguous with the fitting portion (18a) and having an outer diameter larger than the inner diameter of the fitting portion (18a) when fitted in the spring fitting groove (26), a valve support portion (18e) supporting the valve element (16), and an expanding-contracting portion (18c) extending between the locking portion (18b) and the valve support portion (18c) to expand and contract. When the coil spring (18) is compressed, the locking portion (18b) is supported by the fitting portion (18a) and thus prevented from passing through the fitting portion (18a).