Dual-Thread Setting Bolt for Fast Removable Joining

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Solution Overview

Problem

Existing joining elements require pre-drilling and lengthy cycle times for connecting components, and are difficult to remove without causing damage.

Innovation Solution

A nail with a self-tapping and non-self-tapping threaded sections that allows for non-pre-drilled connections and easy detachment by applying torque in opposite directions, using a pulsed force impulse for insertion and rotation for joining and releasing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If flow-form screwing is used to join non-pre-drilled components, then the connection can be made without pre-drilling, but the cycle time becomes relatively long due to friction heating and material hardening requirements

Engineering Contradiction:
Improveconnection without pre-drillingVSAvoidcycle time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent replaces the thermal-mechanical flow-forming process with a purely mechanical insertion process. The nail is driven axially into pre-formed holes through impact or pressing forces, eliminating the need for friction heating and subsequent material hardening time. The thread formation occurs mechanically during insertion rather than through thermal plasticization.

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

Solution Approach 2:

The patent uses pre-formed holes in the components instead of creating holes through friction heating during the joining process. This preliminary preparation of holes allows for rapid nail insertion without the time-consuming thermal softening and hardening cycles required by flow-form screws.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If a two-part nail with hollow shaft is used for non-pre-drilled connections, then positive and non-positive joining can be created with little effort, but the nail becomes difficult to remove without damage to components

Engineering Contradiction:
Improvejoining connection effortVSAvoidnail removal
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The patent divides the nail into two functional segments: a shaft portion with threads for engagement and a head portion with a drive feature. This segmentation allows the shaft to be inserted and engaged while the head remains accessible for torque application during both installation and removal operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a drive feature (such as a hexagonal or cross-shaped recess) in the head as an intermediary mechanism. This drive feature enables torque transmission for both driving the nail in and extracting it, solving the removal difficulty without requiring damage to the components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If a nail with self-forming thread is used for rapid insertion, then non-destructive connections can be made, but the nail requires torque application for detachment which complicates the design

Engineering Contradiction:
Improveconnection speedVSAvoidnail design
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent designs the head to serve multiple functions: it provides bearing surface support during insertion, contains the drive feature for torque application during both installation and removal, and maintains structural integrity throughout the process. This multi-functionality reduces overall design complexity despite the added capability for controlled detachment.

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

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 rapid, non-destructive connections and detachments of components without pre-drilling, reducing cycle times and minimizing damage during assembly and disassembly.

Implementation Method 1

The shaft (30) has, facing towards the head (10), a first axial threaded portion (40) with a self-forming thread (44)

Methodology Applied
Scientific EffectSelf-tapping thread formation: Plasticity

Implementation Method 2

a first axial threaded portion (40) with a self-forming thread (44), facing away from the head (10), with a supporting thread (46) which is not self-forming

Methodology Applied
Scientific EffectMechanical threading: Screw

Data Source

PatentEP4575241A1Setting bolt with shaft thread and drive feature
Publication Date: 2025.06.25 BOLLHOFF VERBINDUNGSTECHNIK GMBH
  • EP4575241A1 patent drawingFigure 1~2
  • EP4575241A1 patent drawingFigure 3~4
  • EP4575241A1 patent drawingFigure 5~6

AI summary

A nail for producing a non-destructive, rotatably detachable connection between at least a first and a second component, of which at least one component is not pre-drilled, which has the following features: a head with a side facing away from the shaft, on which a drive feature is arranged, and a side facing towards the shaft with an under-head annular groove, a shaft formed integrally with the head and extending in the axial direction of the nail, which ends in a point at an end opposite the head, in which the shaft has a first axial threaded section facing towards the head with a self-forming thread, a second axial threaded section facing away from the head with a load-bearing and non-self-forming thread and an axial point region.