Valve Coil Spring Structure to Prevent Compression Jamming

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Solution Overview

Problem

Conventional coil springs in pipe couplings can deform and become stuck when subjected to high loads, preventing the valve element from returning to the closed position due to the connecting portion being pushed into the expanding-contracting portion's enlarged diameter.

Innovation Solution

A coil spring design with a connecting portion that includes a first portion extending radially outward, a second portion traversing the valve support, a third portion curving to overlap the end winding, and a fourth portion extending inward to the support winding, preventing the connecting portion from entering the expanding-contracting portion and ensuring stable support of the valve element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the connecting portion is configured to overlap the expanding-contracting portion, then the valve support portion is supported to the expanding-contracting portion, but the connecting portion may be pushed into the inside of the expanding-contracting portion when the outer diameter increases during compression

Engineering Contradiction:
Improvesupport functionVSAvoidshape stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The connecting portion is designed to extend not only axially but also radially outward, utilizing a second dimension (radial direction) to prevent the harmful effect. By making the connecting portion protrude radially beyond the outer diameter of the expanding-contracting portion, it creates a dimensional barrier that prevents the connecting portion from being pushed into the inside of the expanding-contracting portion during compression.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Force

If the coil spring is compressed under high load, then the valve element can be displaced against fluid pressure, but the outer diameter of the expanding-contracting portion increases causing deformation

Engineering Contradiction:
Improveurging forceVSAvoidouter diameter stability
Core Design Contradiction:
ForceVSShape

Solution Approach 1:

The connecting portion is designed in advance with a radial protrusion that extends beyond the maximum expected outer diameter of the expanding-contracting portion. This preliminary configuration creates a preventive barrier that counteracts the harmful effect before it can occur, ensuring that even under high load compression, the connecting portion cannot be pushed into the inside of the expanding-contracting portion.

Inventive Principle:
Principle #9Preliminary anti-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

This configuration prevents the coil spring from becoming deformed and stuck, allowing the valve element to reliably return to the closed position even under high loads, ensuring consistent operation of the pipe coupling.

Implementation Method 1

an expanding-contracting portion (54) extending from the secured portion toward the valve support portion, the expanding-contracting portion being wound a plurality of turns so as to expand and contract in the direction of the longitudinal axis

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

When compressed, a coil spring usually expands slightly in the radial direction, resulting in an increase in the outer diameter

Methodology Applied
Scientific EffectPoisson's effect: Poisson's Effect

Data Source

PatentEP3922878B1Pipe joint having valve and coil spring used in same
Publication Date: 2024.03.06 NITTO KOHKI CO LTD
  • EP3922878B1 patent drawingFigure 1
  • EP3922878B1 patent drawingFigure 2
  • EP3922878B1 patent drawingFigure 3

AI summary

[Technical Problem] Provided is a coil spring for urging a valve element, the coil spring being configured to prevent occurrence of excessive deformation when a high load is applied thereto, even more reliably. [Solution to Problem] A coil spring 18 is disposed in a fluid passage 12 between a cylindrical body 14 and a valve element 16 to urge the valve element 16 toward a closed position. The coil spring 18 comprises a valve support portion 50 supporting the valve element 16, a secured portion 52 secured to an inner peripheral surface 12a of the fluid passage 12, an expanding-contracting portion 54 extending from the secured portion 52, and a connecting portion 56 between the expanding-contracting portion 54 and the valve support portion 50. The connecting portion 56 comprises a first portion 56a curved so as to pass radially outward of an end winding portion 54b of the expanding-contracting portion 54, a second portion 56b passing through the center of the valve support portion 50, a third portion 56c extending curvedly so as to overlap the first portion 56a, and a fourth portion 56d extending to the valve support portion 50. When the coil spring 18 is compressed, the valve support portion 50 is supported to the expanding-contracting portion 54 through the connecting portion 56.