Dual-Thread Nut Locking Arrangement to Prevent Bolt Loosening

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Solution Overview

Problem

Existing methods for locking nuts on pin bolts, especially for large connections, are impractical due to manufacturing difficulties or heaviness of locking mechanisms, and often require complex or heavy components to prevent loosening.

Innovation Solution

A nut-locking element engages with a pin bolt's first threaded portion and includes a second threaded portion with a smaller pitch, combined with a friction portion that expands against the nut to prevent rotation, ensuring secure engagement with a bearing collar and preventing loosening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional locking elements (locking pins, locking discs, castellated nuts) are used to prevent nut loosening, then the reliability of the connection is improved, but the device complexity and manufacturing difficulty increase significantly

Engineering Contradiction:
Improveconnection securityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the locking function with the nut itself by integrating a locking element into the nut structure. The locking element is formed as an integral part of the nut body, eliminating the need for separate locking components like locking pins or locking discs. This merging approach maintains connection security while significantly reducing device complexity and the number of parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The nut is designed to perform multiple functions simultaneously: it provides the primary fastening function through threading engagement with the bolt, and simultaneously provides locking function through the integrated locking element that engages with the bolt's conical portion. This multi-functionality eliminates the need for separate dedicated locking components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If heavy-duty locking mechanisms are used to secure large bolt connections, then the reliability is improved, but the weight and handling difficulty increase

Engineering Contradiction:
Improveconnection securityVSAvoidlocking mechanism weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

By integrating the locking element directly into the nut structure, the patent eliminates the need for separate heavy locking components. The locking function is achieved through the nut's own integrated locking element that engages with the bolt's conical portion, significantly reducing the overall weight of the fastening assembly while maintaining reliability for large bolt connections.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If friction between nut threads and bolt threads is increased to prevent loosening, then the locking effect is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveanti-loosening effectVSAvoidthread engagement precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces a conical portion on the bolt and a corresponding locking element with a conical surface as an intermediary mechanism between the nut and bolt. This conical interface provides a positive mechanical locking action through radial expansion, achieving reliable anti-loosening effect without relying solely on thread friction, thereby reducing the precision requirements for thread engagement.

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 provides a simple and effective method to secure the nut against the bearing collar, preventing loosening and ensuring reliable connections without the need for complex or heavy locking mechanisms.

Implementation Method 1

The nut-locking element includes a friction portion which, when resting against a portion of the nut, prevents the nut from rotating independently of the nut-locking element

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

in order thereby to expand the bearing collar into abutment against a bore in an element in which the pin bolt is to be held

Methodology Applied
Scientific EffectRadial expansion:

Data Source

PatentEP3341619B1Locking arrangement for a nut
Publication Date: 2022.02.16 BOLT NORGE
  • EP3341619B1 patent drawingFigure 1
  • EP3341619B1 patent drawingFigure 2~3
  • EP3341619B1 patent drawingFigure 4~5

AI summary

An arrangement for locking a nut (3) on a pin bolt (1), the nut (3) being arranged to abut against an end face (21) of a bearing collar (2) arranged on a conical portion (11) of the pin bolt (1), and the nut (3) being in engagement with a first threaded portion (121) of the pin bolt (1), and a nut-locking element (4) being provided with a threaded portion (43) arranged to engage with a second threaded portion (122) of the pin bolt (1), the second threaded portion (122) being concentric with and having a smaller thread pitch than the first threaded portion (121), and the nut-locking element (4) being provided with a friction portion (41) arranged to rest supportingly against the nut (3).