Hole-Forming Screw With Rounded Ribs

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Solution Overview

Problem

Existing screw technologies either cut through materials when forming holes, leading to chip formation and material loss, or require significant deformation and heat to create passages, which may not be desirable for all materials and applications.

Innovation Solution

A screw design featuring a hole-forming part with symmetrically arranged, rounded ribs that displace material without cutting, allowing for selective passage formation on either side of the material, utilizing a blunt end piece and controlled rib pitch to promote material displacement and heat-induced deformation for efficient passage creation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If cutting ribs are used to form holes, then hole formation is achieved, but material loss and chip formation occur

Engineering Contradiction:

Improvematerial lossVSAvoidhole formation capability

Core Design Contradiction:

Loss of substanceVSEase of manufacture

Solution Approach 1:

The ribs are designed with rounded contours and specific geometric parameters (radius ratio r1/r2 between 0.5-1.5) that change the material interaction mode from cutting to displacement. This parameter optimization allows the ribs to displace material plastically rather than cut it, eliminating chip formation while maintaining hole formation capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of using sharp cutting edges that remove material, the invention uses rounded ribs that displace material. This inverted approach transforms the hole-forming mechanism from material removal to material displacement, preventing chip formation and material loss

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If a blunt end piece is used for hole formation, then passage formation on one side is achieved, but significant deformation and heat are required

Engineering Contradiction:

Improvepassage position controlVSAvoidheat generation

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The hole-forming part is segmented into multiple functional zones: the blunt end piece for initial penetration and passage formation, followed by ribs for material displacement and thread formation. This segmentation allows each zone to perform its specific function efficiently, reducing overall deformation requirements

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The blunt end piece performs preliminary action by creating the initial passage through the material before the ribs engage. This preliminary hole formation reduces the deformation and heat generation required for subsequent thread formation, as the ribs only need to displace material within the pre-formed passage

Inventive Principle:

Principle #10Preliminary action

3Productivity

If ribs extend over the entire length of the hole-forming part, then material displacement is maximized, but device complexity increases

Engineering Contradiction:

Improvematerial displacement efficiencyVSAvoidrib structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The ribs are strategically positioned at specific locations along the hole-forming part rather than covering the entire length. This local placement optimizes material displacement at critical zones while reducing overall structural complexity and manufacturing difficulty

Inventive Principle:

Principle #3Local quality

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 screw effectively forms passages without material loss or chip formation, allowing for precise control over passage orientation and material retention, suitable for various materials and manufacturing processes.

Implementation Method 1

the sheet being deformed by turning the screw and thus by generating frictional heat

Methodology Applied

Scientific EffectFrictional heating: Friction

Implementation Method 2

due to the pressure acting upon the screw while it is being screwed in

Methodology Applied

Scientific EffectPressure-induced deformation: Pressure Increase

Implementation Method 3

the material of the sheet piece yields to the blunt end piece and thereby forms a hole

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS8348572B2Hole-forming and thread-forming screw

Publication Date: 2013.01.08 EJOT GMBH & CO KG

AI summary

A hole-forming and thread-forming screw for screwing into a sheet piece, including a slotted screw head for accommodating a tool, a threaded shank and a tapering hole-forming part having outer sides with a continuous convex-shaped curve along an entire length thereof, ribs running like threads along the hole-forming part being provided. The hole-forming part ends in a rounded, blunt end piece, and the rounded ribs, which chiplessly displace the material of the sheet part, are situated symmetrically opposite one another and have a pitch that is a multiple of the thread pitch.