Union Nut Pipe Fitting Retaining Ring for Pull-Out Prevention

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Solution Overview

Problem

Conventional pipe detachment preventing devices for union nut pipe fittings require an inner core for effective operation, increasing production costs and risking pipe detachment if the core is omitted, especially under large pulling forces.

Innovation Solution

A pipe detachment preventing device that omits the inner core by using a retaining ring with protruding portions and a locking tool with facing portions, combined with an inclination mechanism that adjusts the retaining ring's position to maintain biting resistance into the joint pipe even when stretched, preventing detachment under large pulling forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inner core is inserted into the joint pipe to prevent detachment, then the pipe connection reliability is improved, but the production cost increases and the device complexity increases

Engineering Contradiction:
Improvepipe connection reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the inner core component from the pipe connection system. Instead of using a separate inner core inserted into the joint pipe, the retaining ring itself is designed with integrated blade portions that directly bite into the joint pipe wall, achieving the same anti-detachment function without the need for an additional inner core component.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of the retaining ring and the anti-detachment mechanism into a single integrated component. The blade portions are formed as integral parts of the retaining ring body, combining the pipe retention function and the anti-detachment function into one unified structure, thereby reducing device complexity and eliminating the need for separate inner cores.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If an inner core is inserted into the joint pipe to prevent detachment, then the pipe connection reliability is improved, but the production cost increases

Engineering Contradiction:
Improvepipe connection reliabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the inner core component from the pipe connection system. Instead of using a separate inner core inserted into the joint pipe, the retaining ring itself is designed with integrated blade portions that directly bite into the joint pipe wall, achieving the same anti-detachment function without the need for an additional inner core component.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of the retaining ring and the anti-detachment mechanism into a single integrated component. The blade portions are formed as integral parts of the retaining ring body, combining the pipe retention function and the anti-detachment function into one unified structure, thereby reducing device complexity and eliminating the need for separate inner cores.

Inventive Principle:
Principle #5Merging (Combining)

3Force

If the retaining ring diameter is reduced to make the blade portion bite into the joint pipe, then the anti-detachment force is improved, but the pipe stretching flexibility is reduced

Engineering Contradiction:
Improveanti-detachment forceVSAvoidpipe stretching flexibility
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The invention applies the dynamics principle by making the retaining ring capable of changing its diameter dynamically. The retaining ring is designed to be compressible in the radial direction, allowing it to expand when the pipe needs to stretch and contract when anti-detachment force is needed. This dynamic adaptability enables the blade portions to bite into the pipe wall for prevention while still allowing pipe stretching flexibility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameter of the retaining ring diameter based on operational needs. The retaining ring can change its diameter in response to pipe stretching forces, expanding to accommodate pipe growth while maintaining the ability to compress and bite into the pipe wall for anti-detachment. This parameter change capability resolves the contradiction between fixed biting force and flexible adaptability.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively prevents pipe detachment without an inner core, ensuring the connection remains secure even when the joint pipe is stretched, while allowing for flexible stretching and contraction, thus reducing production costs and enhancing reliability.

Implementation Method 1

a blade portion which is provided on an inner side of the retaining ring body and which bites into the joint pipe due to diameter reduction by the tightening means

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the connection holding means includes an inclination mechanism configured to incline the retaining ring in the pipe axis direction with respect to a reference plane orthogonal to a central axis of the retaining ring body

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3971459B1Pipe detachment preventing device for union nut pipe fitting
Publication Date: 2023.06.21 SK KAWANISHI CO LTD
  • EP3971459B1 patent drawingFigure 1~2
  • EP3971459B1 patent drawingFigure 3~4
  • EP3971459B1 patent drawingFigure 5~6A

AI summary

Provided is a pipe detachment preventing device, for a union nut pipe fitting, which can omit an inner core and which can prevent detachment of a pipe from a pipe fitting even when a large pulling force which stretches the pipe acts. Connection holding means (7) includes an inclination mechanism (8) configured to incline a retaining ring (4A) in a pipe axis direction (X) with respect to a reference plane (P) orthogonal to a central axis (C) of a retaining ring body (40), such that one of a circumferential center portion (40y) and a circumferential end portion (40x) of a retaining ring body (40A) is caused to be closer to a fitting body (2) and the other is moved away from the fitting body (2), when first protruding portions (41) and first facing portions (55) come into contact with each other and a pipe pulling force which stretches a joint pipe (100) is applied to the joint pipe (100).