Pipe Joint Gland Geometry for Uneven Tightening Sealing

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Solution Overview

Problem

Conventional pipe joints require precise control of tightening torque to ensure even distribution, leading to potential seal member slackening and gland deformation, and are time-consuming.

Innovation Solution

A pipe joint design featuring a guide part with a second tapered surface guiding the seal member into the seal member insertion space, allowing for uneven tightening and preventing gland deformation, with a gland structure that includes protrusions and concave portions to manage torque and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If equal tightening torque is applied to all fasteners, then reliable sealing is achieved, but installation time increases and work complexity increases

Engineering Contradiction:

Improvesealing reliabilityVSAvoidinstallation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The guide part with the second tapered surface enables the seal member to self-align and self-guide into the correct position during insertion. This self-guiding mechanism eliminates the need for precise torque control during fastener tightening, allowing workers to tighten fasteners in any sequence without compromising sealing reliability, thereby reducing installation time and complexity

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The second tapered surface is pre-formed on the guide part to create a self-aligning pathway for the seal member. This preliminary geometric configuration ensures that the seal member automatically positions itself correctly before the tightening process begins, preventing slackening even when fasteners are tightened unevenly

Inventive Principle:

Principle #10Preliminary action

2Productivity

If unequal tightening is performed to save time, then installation speed increases, but seal member slackening occurs and sealing reliability deteriorates

Engineering Contradiction:

Improveinstallation speedVSAvoidsealing reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The second tapered surface acts as a preliminary cushioning mechanism that accommodates uneven tightening forces. By providing a gradual, self-aligning pathway, it prevents the seal member from being subjected to sudden uneven stresses that would cause slackening, thus protecting the sealing integrity even when fasteners are tightened in an uneven sequence

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If excessive tightening force is applied, then seal member compression is ensured, but gland deformation occurs and reliability deteriorates

Engineering Contradiction:

Improvesealing reliabilityVSAvoidgland structural stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The guide part with the second tapered surface creates a localized self-aligning mechanism that distributes the compression forces evenly on the seal member. This localized geometric feature ensures that the seal member is compressed uniformly without transmitting excessive or uneven forces to the gland, thereby preventing gland deformation while maintaining sealing reliability

Inventive Principle:

Principle #3Local quality

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

Enables reliable sealing without requiring equal tightening torque, reducing installation time and preventing gland deformation even under uneven tightening conditions.

Implementation Method 1

a guide part for guiding the bulb part of the seal member from the opening end face of the socket into the seal member insertion space is formed on the inner circumference of the socket; the guide part has a second tapered surface which decreases in diameter progressively toward the rear side of the socket

Methodology Applied

Scientific EffectTapered surface guidance: Geometry

Implementation Method 2

The seal member 107 has, at one end part in an insertion direction C, a bulb part 118 which is compressed in the pipe diameter direction B and exerts a sealing function

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 3

a gland for pressing the seal member from an opening end face of the socket into the seal member insertion space is externally fitted to the spigot and faces the opening end face of the socket from outside; the gland is attached to the socket through a plurality of fasteners

Methodology Applied

Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentUS12442472B2Pipe joint, gland, and method for joining pipes

Publication Date: 2025.10.14 KUBOTA CORP

AI summary

A pipe joint is provided in which a seal member insertion space 14 is formed between a first tapered surface 8 of a socket 5 and an outer circumference of a spigot 3, a seal member 15 is inserted into the seal member insertion space 14, and a gland 17 that presses the seal member 15 into the seal member insertion space 14 is externally fitted to the spigot 3. The seal member 15 has a bulb part 26 at one end part thereof. A guide part 29 that guides the bulb part 26 from an opening end face 16 of the socket 5 into the seal member insertion space 14 is formed on the inner circumference of the socket 5. The guide part 29 has a second tapered surface 30. An angle of inclination of the second tapered surface 30 is greater than an angle of inclination of the first tapered surface 8.