Low-Profile Lock Ring Assembly for Uniform Mechanical Seal Clamping

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Solution Overview

Problem

Conventional mechanical seals face issues with over-tightening of locking screws, which can damage the lock ring and shaft, and require replacement of the entire assembly if tightening mechanisms fail.

Innovation Solution

A lock ring assembly with a barrel nut and bolt system that allows for adjustable tightening, reducing bending stresses and enabling more torque transfer, featuring flex regions and a single-point tightening mechanism to enhance structural integrity and uniform clamping force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional locking screws are used to secure gland halves, then the seal components can be assembled and tightened, but the user may inadvertently over-tighten the locking screws, thus applying unwanted pressure to the lock ring and damaging it

Engineering Contradiction:
Improvetightening operationVSAvoidunwanted pressure to lock ring
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A polyaxial adjustment mechanism is introduced as an intermediary between the locking screw and the lock ring. This mechanism includes a polyaxial bolt that can adjust its orientation and a barrel nut that provides controlled tightening, mediating the force transmission to prevent direct over-tightening damage to the lock ring while still achieving secure fastening

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If integrated set screws are used in conventional lock ring assemblies, then the sleeve assembly can be mounted to the shaft, but the set screws can be inadvertently overtightened and can damage the shaft

Engineering Contradiction:
Improvemounting operationVSAvoiddamage to shaft
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The polyaxial adjustment mechanism serves as an intermediary between the locking screw and the lock ring, providing controlled force transmission. The polyaxial bolt's ability to adjust orientation and the barrel nut's controlled tightening prevent excessive force from being transmitted to the lock ring and subsequently to the shaft, eliminating the need for damaging set screws

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional tightening mechanisms are used, then the lock ring assembly can be secured, but if a set screw or tightening mechanism fails, then the entire lock ring assembly needs to be replaced

Engineering Contradiction:
Improvesecuring functionVSAvoidreplacement requirement
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The lock ring assembly is segmented into distinct, independently replaceable components: the lock ring itself, the polyaxial adjustment mechanism (including polyaxial bolt and barrel nut), and the locking screw. This segmentation allows individual components to be replaced if they fail, rather than requiring replacement of the entire assembly, improving ease of repair while maintaining reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The segmented design enables selective replacement of only the failed component (e.g., just the polyaxial bolt or just the locking screw) while retaining functional components. This reduces waste and repair costs compared to replacing the entire assembly, while the robust securing function is maintained through the reliable polyaxial adjustment mechanism

Inventive Principle:
Principle #34Discarding and recovering

4Ease of manufacture

If material is removed from the lock ring to accommodate traditional locking elements, then the locking mechanism can be installed, but the structural integrity of the lock ring is reduced

Engineering Contradiction:
Improvelocking element installationVSAvoidstructural integrity of lock ring
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The locking function is separated from the lock ring body by using an external polyaxial adjustment mechanism. This eliminates the need to remove material from the lock ring to create cavities or recesses for traditional locking elements, preserving the lock ring's structural integrity while still providing effective locking capability through the segmented design

Inventive Principle:
Principle #1Segmentation

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 provides improved structural integrity and uniform clamping force, reducing the risk of damage and allowing for efficient torque transfer without over-tightening, with the option to replace individual components instead of the entire assembly.

Implementation Method 1

The lock ring also includes a plurality of flex regions in the form of notches that allow the lock ring to flex when the main body is tightened about the shaft

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The locking mechanism can include a nut element, such as a barrel nut, that allows an associated bolt element to adjust a tightening load and position while clamping occurs of the components of the mechanical seal

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The barrel nut allows for more material to remain in the lock ring, thus providing for additional overall strength relative to a traditional locking element

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP4162179B1Single point actuation low-profile lock ring for a mechanical seal
Publication Date: 2025.09.24 CHESTERTON AW CO
  • EP4162179B1 patent drawingFigure 1~2
  • EP4162179B1 patent drawingFigure 3~4
  • EP4162179B1 patent drawingFigure 5~6

AI summary

A mechanical seal (10) that employs a lock ring assembly (20, 22) having associated therewith a locking mechanism. The locking mechanism can include a nut element (26), such as a barrel nut, that allows an associated bolt element (24) to adjust a tightening load and position while clamping occurs of the components of the mechanical seal. This adjustment flexibility removes or reduces unwanted bending stresses in the bolt element, thus allowing for more torque to translate directly to the lock ring. The barrel nut allows for more material to remain in the lock ring, thus providing for additional overall strength relative to a traditional locking element. The lock ring also includes a plurality of flex regions in the form of notches (80) that allow the lock ring to flex when the main body (32, 50) is tightened about the shaft (12).