Twin-Helix Screwbolt Assembly for Vibration-Resistant Locking

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Solution Overview

Problem

Screwbolts tend to loosen due to vibration, stress, and other operational factors in mechanical systems, requiring frequent inspection and re-tightening in applications like railways and construction, which is costly and inefficient.

Innovation Solution

A screwthreaded fastening system with a shank component having a greater surface hardness and a nut component with a hardness range of 10-200 HB, featuring a twin helix thread configuration that induces frictional welding when torque is applied, providing a secure and vibration-proof fixing by generating heat at the contact surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional screwthreaded fastening systems are used, then the fastening can be easily installed, but the fastener loosens due to vibration and operational stresses

Engineering Contradiction:
Improveresistance to looseningVSAvoidfastening system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the harmful effect of vibration and relative movement, which traditionally causes loosening, into a beneficial frictional welding process. The controlled relative movement between the harder shank component and softer nut component generates heat and friction that welds the surfaces together, transforming the loosening mechanism into a locking mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the physical parameters of the fastening components by specifying different hardness values for the shank component (greater surface hardness) and nut component (10-200 HB hardness). This parameter difference enables the frictional welding mechanism to occur during tightening, creating a permanent bond that prevents loosening.

Inventive Principle:
Principle #35Parameter changes

2Strength

If torque is applied to tighten the fastener, then the fastening strength increases, but the components may deform or fail

Engineering Contradiction:
Improvefastening strengthVSAvoidcomponent deformation
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a hardness gradient between components - the shank component has greater surface hardness at the contact area while the nut component has controlled hardness (10-200 HB). This localized hardness difference ensures that during torque application, the softer nut deforms plastically to accommodate the harder shank, distributing stress and preventing catastrophic failure while achieving strong fastening.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The controlled deformation of the softer nut component during tightening is converted into a beneficial frictional welding process. The plastic deformation increases surface contact area and friction, generating heat that welds the surfaces together, transforming potential damage into a permanent, strong bond.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If standard hardness materials are used for both components, then manufacturing is easier, but frictional welding cannot occur

Engineering Contradiction:
Improvemanufacturing easeVSAvoidfrictional welding capability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the material parameter of hardness for the two components - specifying that the shank component has greater surface hardness while the nut component has hardness in the range of 10-200 HB. This parameter differentiation enables the frictional welding mechanism to occur during normal tightening operations, achieving reliable vibration-proof fastening.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material properties by using two different hardness等级的 materials for the shank and nut components. This composite approach, with the harder shank and softer nut, creates the necessary conditions for frictional welding while maintaining manufacturability through standard heat treatment processes.

Inventive Principle:
Principle #40Composite materials

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 significantly reduces the tendency of screwbolts to unfasten over time, enhancing the resistance to loosening and allowing for fewer inspection procedures, thereby improving efficiency and reducing costs in various engineering and construction applications.

Implementation Method 1

the application of torque in rotating a first metallic fastening component of a first hardness relative to a second metallic fastening of a second hardness must be maintained to ensure that the frictional forces induce frictional welding between the surfaces

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the frictional forces induce frictional welding between the surfaces such that upon ceasing relative movement, the first and second parts become welded with respect to their mutual engaging contact surfaces

Methodology Applied
Scientific EffectFriction welding: Friction Welding

Data Source

PatentEP3532739B1Improvements in or relating to screwbolts
Publication Date: 2024.01.17 EXCALIBUR SCREWBOLTS
  • EP3532739B1 patent drawingFigure 1~2ii
  • EP3532739B1 patent drawingFigure 3~4
  • EP3532739B1 patent drawingFigure 5~6ii

AI summary

The present invention relates to fasteners such as screwbolts in general and to anti-shake screwthreaded systems and anti-shake screwthreaded assemblies employing screwbolts (50) in particular. As is universally known, in relation to screws and threaded fasteners, a thread comprise a continuous helical ridge formed on the inside (nut) or outside (screw) of a cylinder. An issue of concern for all types of screw fasteners is that if they rotate relative to a fastened item, they diminish the degree of fastening. Many methods of preventing a relative rotation between bolt and nut have been devised. The present invention seeks to provide an improved screwbolt system for use in engineering and construction. The present invention also seeks to provide a screwbolt for use as a fastener in harsh conditions of load and have a reduced tendency to unfasten. The present invention also seeks to provide a method of installing such screwbolts (50).