Thread-Forming Element With Conical Tapping Elements

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing threaded elements face issues with imperfect coupling due to variable precision from worn machine tools, leading to play between threads, which can result in unscrewing under thermal shocks or vibrations, and require costly dimensional checks and adhesive use, limiting their application.

Innovation Solution

A thread-forming element with a cylindrical body and helical thread featuring conical tapping elements with a hexahedral shape, which plastically deforms the material to form a strong, interference-free thread without adhesives, accommodating standard screws and withstanding mechanical stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If threaded elements are produced with machine tools subject to wear, then mass production is achieved, but manufacturing precision deteriorates leading to imperfect coupling

Engineering Contradiction:
Improvemass production capabilityVSAvoidthread dimensional precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention changes the fundamental parameter of thread formation from material removal (cutting) to material plastic deformation. The conical tapping elements cold-form the female thread by plastically deforming the hole material, which eliminates sensitivity to machine tool wear and achieves consistent manufacturing precision regardless of production volume or tool condition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the traditional mechanical cutting system (threading die and threading tap) with a cold-forming system. Instead of using cutting tools that wear and require precision maintenance, the patent uses conical tapping elements that plastically deform the material to create the female thread, substituting a wear-resistant forming mechanism for a wear-prone cutting mechanism.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If dimensional checks are performed to ensure constant interference between threads, then coupling precision is improved, but production cost increases

Engineering Contradiction:
Improvethread interference consistencyVSAvoidinspection process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The conical tapping elements create female threads through self-contained plastic deformation of the material. The cold-forming process inherently produces consistent thread geometry without requiring external inspection or adjustment mechanisms, making the system self-regulating and eliminating the need for costly dimensional checking equipment and procedures.

Inventive Principle:
Principle #25Self-service

3Reliability

If adhesives are used to dampen mechanical stresses, then reliability is improved, but device complexity and production cost increase

Engineering Contradiction:
Improvecoupling resistance to mechanical stressesVSAvoidadditional processing steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the adhesive layer from the screw/female screw coupling system. By creating a cold-formed female thread with optimal interference fit through plastic deformation, the patent achieves sufficient mechanical stress resistance without requiring additional adhesive materials or the processing steps associated with adhesive application and curing.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of manufacture

If self-tapping screws create female screw by material removal, then ease of manufacture is improved, but harmful factors increase due to shavings damaging thread crests

Engineering Contradiction:
Improvefemale screw creation capabilityVSAvoidthread crest damage from shavings
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention replaces the material removal mechanism (cutting) with a material plastic deformation mechanism. The conical tapping elements cold-form the female thread by displacing and compressing the material rather than removing it, which eliminates the generation of shavings and prevents damage to the newly formed thread crests while maintaining ease of manufacture.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution achieves a perfectly adherent, stress-resistant screw/female screw coupling that can withstand multiple tightening and loosening cycles without adhesives, reducing production costs and ensuring secure fastening.

Implementation Method 1

said thread-forming element, particularly for holes made in cold-deformable materials

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

said tapping element having a hexahedral shape with a triangular base

Methodology Applied
Scientific EffectCold-forming: Cold-forming

Data Source

PatentEP2545291B1Thread-forming element, particularly for holes made in cold-deformable materials
Publication Date: 2015.01.21 BONGIORNO TERESA CELSA
  • EP2545291B1 patent drawingFigure 1~2
  • EP2545291B1 patent drawingFigure 3~4
  • EP2545291B1 patent drawingFigure 5~6

AI summary

The present invention relates to a thread-forming element, particularly for holes made in cold-deformable materials, comprising a cylindrical body (2) with a circular cross-section which has on at least part of its outer surface a helical thread (4). The helical thread (4) extends in proximity to at least one conical end (5) of the cylindrical body (2). The distinctive characteristic of the thread-forming element (1) consists in the fact that on the surface of the end (5) there is at least one tapping element (6), which has a hexahedral shape with a triangular base.