Sleeved Nut Locking Structure for Compact Shear-Resistant Joints

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Solution Overview

Problem

Existing bolted joints face challenges with access constraints in compact assemblies and shear forces, which can lead to slipping and require larger bolts, conflicting with the trend towards smaller and more compact designs.

Innovation Solution

A nut with a sleeve that extends perpendicularly from the nut head, configured to press fit into receiving parts and align them, creating a mechanical lock that reduces shear forces and allows for smaller bolt sizes without sacrificing clamping force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If larger bolts are used to generate more friction or clamping force to prevent slipping, then the bolted joint can withstand shear forces better, but the assembly size increases and conflicts with compact design trends

Engineering Contradiction:
Improvebolted joint stabilityVSAvoidassembly size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent introduces a sleeve as an intermediary component between the bolt and the receiving parts. This sleeve creates a mechanical lock that directly resists shear forces, eliminating the need to increase bolt size for friction-based locking. The sleeve acts as a mediator that transfers and distributes loads, allowing compact bolt dimensions while maintaining joint stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention segments the load-bearing function into two separate components: the bolt provides clamping force, while the sleeve provides mechanical locking against shear forces. This segmentation allows each component to be optimized independently - the bolt can remain small for compact design, while the sleeve handles the shear resistance function that would otherwise require a larger bolt.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If serration bolts are used to create locking features and avoid slipping, then clamping force is maintained with smaller bolts, but access to both sides of the receiving part is required during assembly

Engineering Contradiction:
Improvebolt sizeVSAvoidassembly accessibility
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent extracts the mechanical locking function from the bolt itself and places it in a separate sleeve component. This extraction allows the bolt to be simple and small without requiring complex serrations or features that would need bilateral access. The sleeve, which provides the locking mechanism, is installed in a way that does not require access to both sides of the assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If larger bolts are used to generate more friction to prevent slipping, then the bolted joint can withstand shear forces better, but the clamping force requirement increases

Engineering Contradiction:
Improveshear force resistanceVSAvoidclamping force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The sleeve serves as a mechanical intermediary that directly engages with the receiving parts to resist shear forces through interference fit and mechanical locking. This eliminates the need for the bolt to generate high friction through high clamping force, as the sleeve independently handles shear resistance while the bolt maintains only the necessary clamping force for joint integrity.

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

The nut with a sleeve effectively reduces the need for high clamping force, minimizes slippage, and allows for the use of smaller bolts, thereby reducing assembly costs, material usage, and weight while maintaining assembly integrity.

Implementation Method 1

The exterior surface of the sleeve creates friction or clamping forces between the sleeve and a surface of the receiving parts

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

A nut with a sleeve configured to press fit into one or more receiving parts generates an interference between the sleeve of the nut and the receiving parts in which the sleeve of the nut is forced into an opening of the receiving parts

Methodology Applied
Scientific EffectInterference fit:

Data Source

PatentEP4549758A1Nut sleeve with locking and alignment features
Publication Date: 2025.05.07 VOLVO CAR CORP
  • EP4549758A1 patent drawingFigure 1A~1C
  • EP4549758A1 patent drawingFigure 2~3
  • EP4549758A1 patent drawingFigure 4A~4F

AI summary

A nut comprising a sleeve extending from a nut head of the nut and configured to extend into a first receiving part and a second receiving part, wherein the sleeve comprises; an exterior surface configured to engage with the first receiving part and the second receiving part; and a hollow interior configured to receive a bolt shaft, wherein the sleeve aligns the first receiving part and the second receiving part.