Positive Lock Nut With Helical Insert for Precise Reusable Torque

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Solution Overview

Problem

Current locking fasteners, such as those using Vespel™ inserts, are expensive, easily damaged during installation, and have limited reusability, leading to inconsistencies in locking torque values and high costs, while existing alternatives face issues with durability and assembly complexity.

Innovation Solution

A fastener system comprising a serrated nut with a helical wire insert, where the nut and insert have specific hardness and thermal expansion relationships, allowing for precise torque control and improved thread characteristics, enhancing durability and reusability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resilient inserts such as Vespel™ are used for locking fasteners, then locking torque is provided, but the inserts are expensive, easily damaged during installation, and have limited reusability

Engineering Contradiction:

Improvelocking torque consistencyVSAvoidinstallation difficulty and cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameters from resilient polymer (Vespel™) to metal materials with specific hardness relationships. The nut and insert are made from dissimilar metals with controlled hardness differences, allowing consistent locking torque while improving durability and reusability. This parameter change resolves the contradiction by maintaining reliability through controlled material properties while eliminating the fragility and installation issues of resilient inserts.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategy by using dissimilar metal materials for the nut and insert. This allows combining the advantages of different materials - the structural integrity and reusability of metal with controlled friction characteristics. The dissimilar metal combination provides consistent locking torque across multiple cycles while being more durable and cost-effective than single-material resilient inserts.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If dissimilar material fasteners are used (polymer body with steel alloy threads), then thread characteristics are improved, but material compatibility and thermal expansion differences create challenges

Engineering Contradiction:

Improvethread characteristicsVSAvoidthermal expansion consistency

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent carefully selects and controls the material parameters of dissimilar metals, specifically their coefficients of thermal expansion and hardness. By choosing metal materials with compatible thermal expansion characteristics and controlled hardness relationships, the patent achieves consistent thread characteristics while minimizing thermal expansion differences. This resolves the contradiction by optimizing material parameters to satisfy both precision and temperature stability requirements.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If castellated nuts with pins or wire inserts are used for positive locking, then shaft position is secured, but the system lacks precision torque control and has limited adaptability

Engineering Contradiction:

Improvepositive locking capabilityVSAvoidtorque control precision

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a multi-functional fastener system that combines both positive locking capability and precision torque control in a single mechanism. The serrated interface provides positive locking like castellated nuts, while the controlled friction characteristics enable precise torque control. This universal design resolves the contradiction by integrating the functions of both systems, making the fastener adaptable to applications requiring both security and precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 system provides consistent locking torque over multiple cycles, reduces installation difficulties, and improves maintainability, while being cost-effective and resistant to vibration and temperature variations, with enhanced tensile strength and reduced material costs.

Implementation Method 1

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

the nut and insert have specific hardness and thermal expansion relationships, allowing for precise torque control and improved thread characteristics, enhancing durability and reusability

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12448997B2Precision torque control positive lock nut

Publication Date: 2025.10.21 BPC LG 2 LLC

AI summary

A torque control fastener system having a fastener nut, a helical wire insert, and a shaft, where the nut and helical wire insert have unique hardness and coefficient of thermal expansion relationships that produce improved performance.