Axial Bolt Locking Assembly Without Transverse Clearance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing bolt locking systems require transverse clearance to function effectively, which is not always feasible or available, leading to inefficiencies in immobilizing nuts relative to threaded rods.

Innovation Solution

A bolt locking system comprising a housing within the threaded rod, a first part that cooperates with the nut to immobilize it in translation and/or rotation, and a locking screw that expands to occupy the housing, allowing immobilization without needing transverse clearance, utilizing parts with complementary cross-sections and slots for expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transverse pin is used to immobilize the nut in rotation, then the locking reliability is improved, but the requirement for transverse clearance increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidadaptability to applications without transverse clearance
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention transitions from a transverse locking approach (perpendicular to the bolt axis) to an axial locking approach (parallel to the bolt axis). The locking mechanism is repositioned along the axial dimension, allowing the pin to be inserted through the bolt head rather than requiring transverse clearance. This dimensional shift resolves the contradiction by maintaining locking reliability while eliminating the clearance requirement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of inserting the locking pin through the nut body as in conventional systems, the invention inverts the approach by inserting the pin through the bolt head and having it engage with the nut from the opposite direction. This inversion allows the locking mechanism to function without requiring transverse clearance in the nut, thereby resolving the contradiction between reliability and adaptability.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If a locking system is added to prevent untimely unscrewing, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveanti-loosening reliabilityVSAvoidlocking system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the locking pin with the bolt head structure, making the locking mechanism an integrated part of the bolt rather than a separate component. The pin is positioned within the bolt head and engages with the nut through the threaded rod, combining multiple functions into a unified structure. This reduces device complexity while maintaining anti-loosening reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bolt head is designed to serve multiple functions: it provides the conventional head function for tool engagement, houses the locking pin mechanism, and facilitates the axial insertion of the pin through its hollow structure. This multi-functionality reduces the need for additional separate components, thereby reducing overall device complexity while ensuring reliable locking.

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

3Ease of operation

If clearance is provided in the transverse direction for pin insertion, then the ease of operation is improved, but the manufacturing precision requirements worsen

Engineering Contradiction:
Improvepin insertion easeVSAvoidtransverse clearance precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention changes the insertion direction from transverse to axial. The pin is inserted through the bolt head along the axial direction, which is already a controlled dimension in bolt manufacturing. This eliminates the need for additional transverse clearance and associated precision requirements, while maintaining ease of operation through the straightforward axial insertion path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 secure immobilization of the nut in both translation and rotation relative to the threaded rod without requiring transverse clearance, enhancing the reliability and precision of the locking mechanism.

Implementation Method 1

the first section of the second part being expandable and configured to occupy a retracted state in which the first section can slide in the housing and an expanded state in which the second part is immobilized in the housing of the threaded rod

Methodology Applied
Scientific EffectElastic expansion: Elasticity

Implementation Method 2

a locking screw having a head resting against the first part as well as a threaded rod passing through the passage hole and screwing into the second part to immobilize the first and second parts in translation relative to each other

Methodology Applied
Scientific EffectThreaded fastening: Screw

Implementation Method 3

the second section of the second part and the passage hole of the first part have identical cross sections comprising at least one flat... the first part is expandable and configured to occupy a retracted state in which the first section can slide in the housing

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP3916249B1Bolt provided with a system for blocking axial rotation and assembly comprising at least one such bolt
Publication Date: 2023.04.12 AIRBUS (SAS)
  • EP3916249B1 patent drawingFigure 1
  • EP3916249B1 patent drawingFigure 2
  • EP3916249B1 patent drawingFigure 3

AI summary

The invention relates to a bolt comprising a locking system (24) preventing a nut (18) from loosening relative to a threaded rod (16.1) and comprising: - a housing (26) positioned in the threaded rod (16.1), - a first portion (30) cooperating with the nut (18) so as to immobilize it against translation and/or rotation and having a through hole (36) passing through it, - a second portion (38) partially housed in the housing (26) of the threaded rod (16.1) and in the through hole (36) of the first portion (30), having a cross-section configured to immobilize the first portion (30) against rotation relative to the threaded rod (16.1) and comprising an expandable section (38.1) to immobilize it in the housing (26) of the threaded rod (16.1) in the expanded state, - a locking screw (46) screwing into the second part (38) to immobilize the first and second parts (30, 38) in translation relative to each other.