Threaded Fastener Friction Treatments to Prevent Galling

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Solution Overview

Problem

Industrial bolting applications face challenges with existing tools that suffer from side load and thread galling due to friction and adhesion, leading to material wear and difficulties in loosening corroded fasteners, especially in high load, low speed conditions, where traditional washers do not effectively minimize these issues.

Innovation Solution

The HYTORC Z System employs multi-speed/multi-torque mode tools with torque multiplication and vibration mechanisms, using Z Washers with friction coefficient increasing treatments to prevent washer rotation and ensure consistent bolt load, and Z Sockets for dual drive coaxial action and reaction, eliminating external reaction abutments and minimizing side loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional washers are used, then the structure is simple and easy to manufacture, but side load and thread galling occur due to friction and adhesion

Engineering Contradiction:

Improvewasher manufacturing simplicityVSAvoidside load and thread galling

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The washer surface is treated to create localized friction coefficient increasing treatments in specific areas. This means different regions of the washer surface have different friction characteristics - some areas have higher friction to prevent rotation while allowing controlled movement in other areas, thereby reducing side load and thread galling without requiring complete redesign of the washer structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The friction coefficient of the washer surface is modified through surface treatments such as knurling, coating, or heat treatment. By changing the friction parameter locally on the washer surface, the system achieves reduced side load and prevention of thread galling while maintaining the simple washer structure and ease of manufacture

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If friction coefficient increasing treatments are applied to the washer, then side load and thread galling are reduced, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveside load and thread gallingVSAvoidwasher manufacturing complexity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

Instead of treating the entire washer surface, friction coefficient increasing treatments are applied only to specific localized areas where they are most effective. This selective treatment approach reduces the complexity of the manufacturing process compared to full-surface treatment, while still achieving the goal of reducing side load and thread galling

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The friction coefficient increasing treatments use cost-effective surface modification methods such as knurling patterns, standard coatings, or heat treatment processes that are readily available and easy to apply. These treatments provide sufficient functionality without requiring expensive or complex manufacturing processes

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If torque multiplication mechanisms are used, then bolting speed and accuracy are improved, but operator vibration increases

Engineering Contradiction:

Improvebolting speed and accuracyVSAvoidoperator vibration

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The washer with friction coefficient increasing treatments acts as an intermediary element between the fastener and the joint. By controlling friction at the washer interface, the system reduces vibration transmission to the operator while maintaining the torque multiplication effects for improved bolting speed and accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution enables faster, safer, and more accurate bolting with reduced operator vibration, effective loosening of corroded fasteners, and prevention of thread galling, by maintaining consistent torque and friction distribution across the bolt and nut interface.

Implementation Method 1

multi-speed/multi-torque mode tools with torque multiplication and vibration mechanisms

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 2

side load and thread galling due to friction and adhesion

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

Z Washers with friction coefficient increasing treatments to prevent washer rotation

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 4

multi-speed/multi-torque mode tools with torque multiplication

Methodology Applied

Scientific EffectTorque: Torque

Data Source

PatentEP3423236B1Threaded fastener with friction coefficient increasing treatments

Publication Date: 2022.08.17 HYTORC DIV UNEX CORP

Figure 1A~1C
Figure 2A~2B
Figure 3A~3C

AI summary

The invention is related to a threaded fastener for fastening objects including: a stud rotatably coupled to a stud-head having a bottom surface; and the bottom surface having friction coefficient increasing treatments biased in areas outward from the stud.